layout specihern

Updated the `StatusTranslated` property to cast the `Status` integer to the `Constants.EnvelopeStatus` enum before calling `ToString()`. This ensures accurate string representation based on the enum rather than the integer value.

.gitignore

@@ -361,3 +361,7 @@ MigrationBackup/
 
 # Fody - auto-generated XML schema
 FodyWeavers.xsd
+/EnvelopeGenerator.Web/.config/dotnet-tools.json
+/EnvelopeGenerator.GeneratorAPI/ClientApp/envelope-generator-ui/.vscode
+/EnvelopeGenerator.Tests.Application/Services/BugFixTests.cs
+/EnvelopeGenerator.Tests.Application/annotations.json

EnvelopeGenerator.Application/Configurations/AuthenticatorParams.cs

@@ -0,0 +1,33 @@
+namespace EnvelopeGenerator.Application.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class AuthenticatorParams
+{
+    /// <summary>
+    /// Default value is 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890123456789012345678901234567890123456789'
+    /// </summary>
+    public string CharPool { get; init; } = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890123456789012345678901234567890123456789";
+
+    //TODO: Increase the DefaultTotpSecretKeyLength (e.g. to 32) but make sure that the QR code is generated correctly and can be scanned by the authenticator.
+    /// <summary>
+    /// Default value is 20
+    /// </summary>
+    public int DefaultTotpSecretKeyLength { get; init; } = 20;
+
+    /// <summary>
+    /// Default value is 
+    /// </summary>
+    public string TotpIssuer { get; init; } = "signFlow";
+
+    /// <summary>
+    /// 0 is user email, 1 is secret key and 2 is issuer.
+    /// </summary>
+    public string TotpUrlFormat { get; init; } = "otpauth://totp/{0}?secret={1}&issuer={2}";
+
+    /// <summary>
+    /// Default value is 20.
+    /// </summary>
+    public int TotpQRPixelsPerModule { get; init; } = 20;
+}

EnvelopeGenerator.Application/Configurations/DbTriggerParams.cs

@@ -0,0 +1,8 @@
+namespace EnvelopeGenerator.Application.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class DbTriggerParams : Dictionary<string, ICollection<string>>
+{
+}

EnvelopeGenerator.Application/Configurations/DispatcherParams.cs

@@ -0,0 +1,27 @@
+namespace EnvelopeGenerator.Application.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class DispatcherParams
+{
+    /// <summary>
+    /// Default value is 1
+    /// </summary>
+    public int SendingProfile { get; init; } = 1;
+
+    /// <summary>
+    /// Defalt value is 'DDEnvelopGenerator'
+    /// </summary>
+    public string AddedWho { get; init; } = "DDEnvelopGenerator";
+
+    /// <summary>
+    /// Default value is 202377
+    /// </summary>
+    public int ReminderTypeId { get; init; } = 202377;
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    public string EmailAttmt1 { get; init; } = string.Empty;
+}

EnvelopeGenerator.Application/Configurations/GtxMessagingParams.cs

@@ -0,0 +1,37 @@
+using DigitalData.Core.Client.Interface;
+namespace EnvelopeGenerator.Application.Configurations;
+
+/// <summary>
+/// https://www.gtx-messaging.com/en/api-docs/sms-rest-api/
+/// </summary>
+public class GtxMessagingParams : IHttpClientOptions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public required string Uri { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? Path { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public Dictionary<string, object>? Headers { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public Dictionary<string, object?>? QueryParams { get; init; }
+    /// <summary>
+    /// Default value is 'to'
+    /// </summary>
+    public string RecipientQueryParamName { get; init; } = "to";
+
+    /// <summary>
+    /// Default value is 'text'
+    /// </summary>
+    public string MessageQueryParamName { get; init; } = "text";
+}

EnvelopeGenerator.Application/Configurations/MailParams.cs

@@ -0,0 +1,12 @@
+namespace EnvelopeGenerator.Application.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class MailParams
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public required Dictionary<string, string> Placeholders { get; init; }
+}

EnvelopeGenerator.Application/Configurations/TotpSmsParams.cs

@@ -0,0 +1,81 @@
+using OtpNet;
+using System.Globalization;
+
+namespace EnvelopeGenerator.Application.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class TotpSmsParams
+{
+    /// <summary>
+    /// The unit is second.
+    /// </summary>
+    public int TotpStep { get; init; } = 90;
+
+    /// <summary>
+    /// Default value is 'Ihr 2FA-Passwort lautet {0}. Gültig bis {1}'
+    /// </summary>
+    public string Format { get; init; } = "Ihr 2FA-Passwort lautet {0}. Gültig bis {1}";
+    
+    /// <summary>
+    /// 
+    /// </summary>
+    public ExpirationHandler Expiration { get; init; } = new();
+
+    /// <summary>
+    /// Default value is VerificationWindow.RfcSpecifiedNetworkDelay
+    /// </summary>
+    public VerificationWindow? TotpVerificationWindow { get; private init; } = VerificationWindow.RfcSpecifiedNetworkDelay;
+
+    private IEnumerable<int>? _tvwParams;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public IEnumerable<int>? TotpVerificationWindowParams
+    {
+        get => _tvwParams;
+        init
+        {
+            _tvwParams = value;
+            if(_tvwParams is not null)
+                TotpVerificationWindow = new(previous: _tvwParams.ElementAtOrDefault(0), future: _tvwParams.ElementAtOrDefault(0));
+        }
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public class ExpirationHandler
+    {
+        /// <summary>
+        /// Default value is 'e{0}_r{1}_sms_code_expiration'
+        /// </summary>
+        public string CacheKeyFormat { get; init; } = "e{0}_r{1}_sms_code_expiration";
+
+        /// <summary>
+        /// Default value is HH:mm:ss
+        /// </summary>
+        public string Format { get; init; } = "HH:mm:ss";
+
+        /// <summary>
+        /// Default value is 'de-DE'
+        /// </summary>
+        public string CultureName
+        {
+            get => _cultureInfo.Name;
+            init => _cultureInfo = new(value);
+        }
+
+        /// <summary>
+        /// Default value is 'de-DE'
+        /// </summary>
+        private CultureInfo _cultureInfo = new("de-DE");
+
+        /// <summary>
+        /// Default value is 'de-DE'
+        /// </summary>
+        public CultureInfo CultureInfo => _cultureInfo;
+    }
+}

EnvelopeGenerator.Application/Contracts/Repositories/IConfigRepository.cs

@@ -0,0 +1,17 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IConfigRepository : ICRUDRepository<Config, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<Config?> ReadFirstAsync();
+}

EnvelopeGenerator.Application/Contracts/Repositories/IDocumentReceiverElementRepository.cs

@@ -0,0 +1,11 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IDocumentReceiverElementRepository : ICRUDRepository<DocumentReceiverElement, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Repositories/IDocumentStatusRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IDocumentStatusRepository : ICRUDRepository<DocumentStatus, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEmailTemplateRepository.cs

@@ -0,0 +1,19 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+using static EnvelopeGenerator.Domain.Constants;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEmailTemplateRepository : ICRUDRepository<EmailTemplate, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="type"></param>
+    /// <returns></returns>
+    Task<EmailTemplate?> ReadByNameAsync(EmailTemplateType type);
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEnvelopeCertificateRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+public interface IEnvelopeCertificateRepository : ICRUDRepository<EnvelopeCertificate, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEnvelopeDocumentRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeDocumentRepository : ICRUDRepository<EnvelopeDocument, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEnvelopeHistoryRepository.cs

@@ -0,0 +1,32 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeHistoryRepository : ICRUDRepository<EnvelopeHistory, long>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <param name="status"></param>
+    /// <returns></returns>
+    Task<int> CountAsync(int? envelopeId = null, string? userReference = null, Constants.EnvelopeStatus? status = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <param name="status"></param>
+    /// <param name="withSender"></param>
+    /// <param name="withReceiver"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeHistory>> ReadAsync(int? envelopeId = null, string? userReference = null, Constants.EnvelopeStatus? status = null, bool withSender = false, bool withReceiver = false);
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEnvelopeReceiverReadOnlyRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeReceiverReadOnlyRepository : ICRUDRepository<EnvelopeReceiverReadOnly, long>
+{
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEnvelopeReceiverRepository.cs

@@ -0,0 +1,96 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeReceiverRepository : ICRUDRepository<EnvelopeReceiver, (int Envelope, int Receiver)>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeReceiver>> ReadByUuidAsync(string uuid, bool withEnvelope = true, bool withReceiver = false, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="signature"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeReceiver>> ReadBySignatureAsync(string signature, bool withEnvelope = false, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> ReadByUuidSignatureAsync(string uuid, string signature, bool withEnvelope = true, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<string?> ReadAccessCodeAsync(string uuid, string signature, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<int> CountAsync(string uuid, string signature);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="receiverId"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> ReadByIdAsync(int envelopeId, int receiverId, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="receiverId"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<string?> ReadAccessCodeByIdAsync(int envelopeId, int receiverId, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="username"></param>
+    /// <param name="min_status"></param>
+    /// <param name="max_status"></param>
+    /// <param name="ignore_statuses"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeReceiver>> ReadByUsernameAsync(string username, int? min_status = null, int? max_status = null, params int[] ignore_statuses);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="email"></param>
+    /// <param name="id"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> ReadLastByReceiverAsync(string? email = null, int? id = null, string? signature = null);
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEnvelopeRepository.cs

@@ -0,0 +1,42 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeRepository : ICRUDRepository<Envelope, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="documents"></param>
+    /// <param name="history"></param>
+    /// <param name="documentReceiverElement"></param>
+    /// <returns></returns>
+    Task<IEnumerable<Envelope>> ReadAllWithAsync(bool documents = false, bool history = false, bool documentReceiverElement = false);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="withDocuments"></param>
+    /// <param name="withHistory"></param>
+    /// <param name="withDocumentReceiverElement"></param>
+    /// <param name="withUser"></param>
+    /// <param name="withAll"></param>
+    /// <returns></returns>
+    Task<Envelope?> ReadByUuidAsync(string uuid, bool withDocuments = false, bool withHistory = false, bool withDocumentReceiverElement = false, bool withUser = false, bool withAll = false);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userId"></param>
+    /// <param name="min_status"></param>
+    /// <param name="max_status"></param>
+    /// <param name="ignore_statuses"></param>
+    /// <returns></returns>
+    Task<IEnumerable<Envelope>> ReadByUserAsync(int userId, int? min_status = null, int? max_status = null, params int[] ignore_statuses);
+}

EnvelopeGenerator.Application/Contracts/Repositories/IEnvelopeTypeRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeTypeRepository : ICRUDRepository<EnvelopeType, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Repositories/IReceiverRepository.cs

@@ -0,0 +1,19 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IReceiverRepository : ICRUDRepository<Receiver, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="emailAddress"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<Receiver?> ReadByAsync(string? emailAddress = null, string? signature = null);
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/IDocumentExecutor.cs

@@ -0,0 +1,18 @@
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IDocumentExecutor
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="base64"></param>
+    /// <param name="envelope_uuid"></param>
+    /// <param name="cancellation"></param>
+    /// <returns></returns>
+    Task<EnvelopeDocument> CreateDocumentAsync(string base64, string envelope_uuid, CancellationToken cancellation = default);
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/IEnvelopeExecutor.cs

@@ -0,0 +1,21 @@
+using Dapper;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IEnvelopeExecutor : ISQLExecutor
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userId"></param>
+    /// <param name="title"></param>
+    /// <param name="message"></param>
+    /// <param name="tfaEnabled"></param>
+    /// <param name="cancellation"></param>
+    /// <returns></returns>
+    Task<Envelope> CreateEnvelopeAsync(int userId, string title = "", string message = "", bool tfaEnabled = false, CancellationToken cancellation = default);
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/IEnvelopeReceiverExecutor.cs

@@ -0,0 +1,20 @@
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IEnvelopeReceiverExecutor
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelope_uuid"></param>
+    /// <param name="emailAddress"></param>
+    /// <param name="salutation"></param>
+    /// <param name="phone"></param>
+    /// <param name="cancellation"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> AddEnvelopeReceiverAsync(string envelope_uuid, string emailAddress, string? salutation = null, string? phone = null, CancellationToken cancellation = default);
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/IQuery.cs

@@ -0,0 +1,70 @@
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// Provides methods for executing common queries on a given entity type.
+/// This interface abstracts away the direct usage of ORM libraries (such as Entity Framework) for querying data
+/// and provides asynchronous and synchronous operations for querying a collection or single entity.
+/// </summary>
+/// <typeparam name="TEntity">The type of the entity being queried.</typeparam>
+public interface IQuery<TEntity>
+{
+    /// <summary>
+    /// Asynchronously retrieves the first entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the entity or a default value.</returns>
+    public Task<TEntity?> FirstOrDefaultAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves a single entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the entity or a default value.</returns>
+    public Task<TEntity?> SingleOrDefaultAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves a list of entities.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the list of entities.</returns>
+    public Task<IEnumerable<TEntity>> ToListAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves the first entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the first entity.</returns>
+    public Task<TEntity> FirstAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves a single entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the single entity.</returns>
+    public Task<TEntity> SingleAsync();
+
+    /// <summary>
+    /// Synchronously retrieves the first entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>The first entity or a default value.</returns>
+    public TEntity? FirstOrDefault();
+
+    /// <summary>
+    /// Synchronously retrieves a single entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>The single entity or a default value.</returns>
+    public TEntity? SingleOrDefault();
+
+    /// <summary>
+    /// Synchronously retrieves a list of entities.
+    /// </summary>
+    /// <returns>The list of entities.</returns>
+    public IEnumerable<TEntity> ToList();
+
+    /// <summary>
+    /// Synchronously retrieves the first entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>The first entity.</returns>
+    public TEntity First();
+
+    /// <summary>
+    /// Synchronously retrieves a single entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>The single entity.</returns>
+    public TEntity Single();
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/ISQL.cs

@@ -0,0 +1,20 @@
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// Represents a raw SQL query contract.
+/// </summary>
+public interface ISQL
+{
+    /// <summary>
+    /// Gets the raw SQL query string.
+    /// </summary>
+    string Raw { get; }
+}
+
+/// <summary>
+/// Represents a typed SQL query contract for a specific entity.
+/// </summary>
+/// <typeparam name="TEntity">The type of the entity associated with the SQL query.</typeparam>
+public interface ISQL<TEntity> : ISQL
+{
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/ISQLExecutor.cs

@@ -0,0 +1,27 @@
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// Defines methods for executing raw SQL queries or custom SQL query classes and returning query executors for further operations.
+/// Provides abstraction for raw SQL execution as well as mapping the results to <typeparamref name="TEntity"/> objects.
+/// </summary>
+/// <typeparam name="TEntity">The entity type to which the SQL query results will be mapped.</typeparam>
+public interface ISQLExecutor<TEntity>: ISQLExecutor
+{
+    /// <summary>
+    /// Executes a raw SQL query and returns an <see cref="IQuery{TEntity}"/> for further querying operations on the result.
+    /// </summary>
+    /// <param name="sql">The raw SQL query to execute.</param>
+    /// <param name="cancellation">Optional cancellation token for the operation.</param>
+    /// <param name="parameters">Optional parameters for the SQL query.</param>
+    /// <returns>An <see cref="IQuery{TEntity}"/> instance for further query operations on the result.</returns>
+    IQuery<TEntity> Execute(string sql, CancellationToken cancellation = default, params object[] parameters);
+
+    /// <summary>
+    /// Executes a custom SQL query defined by a class that implements <see cref="ISQL{TEntity}"/> and returns an <see cref="IQuery{TEntity}"/> for further querying operations on the result.
+    /// </summary>
+    /// <typeparam name="TSQL">The type of the custom SQL query class implementing <see cref="ISQL{TEntity}"/>.</typeparam>
+    /// <param name="cancellation">Optional cancellation token for the operation.</param>
+    /// <param name="parameters">Optional parameters for the SQL query.</param>
+    /// <returns>An <see cref="IQuery{TEntity}"/> instance for further query operations on the result.</returns>
+    IQuery<TEntity> Execute<TSQL>(CancellationToken cancellation = default, params object[] parameters) where TSQL : ISQL<TEntity>;
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/ISQLExecutorBaseEntity.cs

@@ -0,0 +1,29 @@
+using Dapper;
+
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// 
+/// </summary>
+public interface ISQLExecutor
+{
+    /// <summary>
+    /// Executes a raw SQL query and returns an <see cref="IQuery{TEntity}"/> for further querying operations on the result.
+    /// </summary>
+    /// <typeparam name="TEntity">The entity type to which the SQL query results will be mapped.</typeparam>
+    /// <param name="sql">The raw SQL query to execute.</param>
+    /// <param name="parameters">Parameters for the SQL query.</param>
+    /// <param name="cancellation">Optional cancellation token for the operation.</param>
+    /// <returns>An <see cref="IQuery{TEntity}"/> instance for further query operations on the result.</returns>
+    Task<IEnumerable<TEntity>> Execute<TEntity>(string sql, DynamicParameters parameters, CancellationToken cancellation = default);
+
+    /// <summary>
+    /// Executes a custom SQL query defined by a class that implements <see cref="ISQL{TEntity}"/> and returns an <see cref="IQuery{TEntity}"/> for further querying operations on the result.
+    /// </summary>
+    /// <typeparam name="TEntity">The entity type to which the SQL query results will be mapped.</typeparam>
+    /// <typeparam name="TSQL">The type of the custom SQL query class implementing <see cref="ISQL{TEntity}"/>.</typeparam>
+    /// <param name="parameters">Parameters for the SQL query.</param>
+    /// <param name="cancellation">Optional cancellation token for the operation.</param>
+    /// <returns>An <see cref="IQuery{TEntity}"/> instance for further query operations on the result.</returns>
+    Task<IEnumerable<TEntity>> Execute<TEntity, TSQL>(DynamicParameters parameters, CancellationToken cancellation = default) where TSQL : ISQL;
+}

EnvelopeGenerator.Application/Contracts/Services/IAuthenticator.cs

@@ -0,0 +1,63 @@
+using OtpNet;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IAuthenticator
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="length"></param>
+    /// <returns></returns>
+    string GenerateCode(int length);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="length"></param>
+    /// <returns></returns>
+    string GenerateTotpSecretKey(int? length = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userEmail"></param>
+    /// <param name="secretKey"></param>
+    /// <param name="issuer"></param>
+    /// <param name="totpUrlFormat"></param>
+    /// <param name="pixelsPerModule"></param>
+    /// <returns></returns>
+    byte[] GenerateTotpQrCode(string userEmail, string secretKey, string? issuer = null, string? totpUrlFormat = null, int? pixelsPerModule = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userEmail"></param>
+    /// <param name="length"></param>
+    /// <param name="issuer"></param>
+    /// <param name="totpUrlFormat"></param>
+    /// <param name="pixelsPerModule"></param>
+    /// <returns></returns>
+    byte[] GenerateTotpQrCode(string userEmail, int? length = null, string? issuer = null, string? totpUrlFormat = null, int? pixelsPerModule = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="secretKey"></param>
+    /// <param name="step"></param>
+    /// <returns></returns>
+    string GenerateTotp(string secretKey, int step = 30);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="totpCode"></param>
+    /// <param name="secretKey"></param>
+    /// <param name="step"></param>
+    /// <param name="window"></param>
+    /// <returns></returns>
+    bool VerifyTotp(string totpCode, string secretKey, int step = 30, VerificationWindow? window = null);
+}

EnvelopeGenerator.Application/Contracts/Services/IConfigService.cs

@@ -0,0 +1,31 @@
+using DigitalData.Core.Abstraction.Application;
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IConfigService : IReadService<ConfigDto, Config, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<DataResult<ConfigDto>> ReadFirstAsync();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<ConfigDto> ReadDefaultAsync();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<string> ReadDefaultSignatureHost();
+}

EnvelopeGenerator.Application/Contracts/Services/IDocumentReceiverElementService.cs

@@ -0,0 +1,13 @@
+using DigitalData.Core.Abstraction.Application;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IDocumentReceiverElementService : IBasicCRUDService<DocumentReceiverElementDto, DocumentReceiverElement, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Services/IDocumentStatusService.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IDocumentStatusService : IBasicCRUDService<DocumentStatusDto, DocumentStatus, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Services/IEmailTemplateService.cs

@@ -0,0 +1,21 @@
+using DigitalData.Core.Abstraction.Application;
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+using static EnvelopeGenerator.Domain.Constants;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEmailTemplateService : IBasicCRUDService<EmailTemplateDto, EmailTemplate, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="type"></param>
+    /// <returns></returns>
+    Task<DataResult<EmailTemplateDto>> ReadByNameAsync(EmailTemplateType type);
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeCertificateService.cs

@@ -0,0 +1,13 @@
+using DigitalData.Core.Abstraction.Application;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeCertificateService : IBasicCRUDService<EnvelopeCertificateDto, EnvelopeCertificate, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeDocumentService.cs

@@ -0,0 +1,13 @@
+using DigitalData.Core.Abstraction.Application;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeDocumentService : IBasicCRUDService<EnvelopeDocumentDto, EnvelopeDocument, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeHistoryService.cs

@@ -0,0 +1,85 @@
+using DigitalData.Core.Abstraction.Application;
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.DTOs.EnvelopeHistory;
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using EnvelopeGenerator.Domain.Entities;
+using static EnvelopeGenerator.Domain.Constants;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeHistoryService : ICRUDService<EnvelopeHistoryCreateDto, EnvelopeHistoryDto, EnvelopeHistory, long>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <param name="status"></param>
+    /// <returns></returns>
+    Task<int> CountAsync(int? envelopeId = null, string? userReference = null, EnvelopeStatus? status = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <returns></returns>
+    Task<bool> AccessCodeAlreadyRequested(int envelopeId, string userReference);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <returns></returns>
+    Task<bool> IsSigned(int envelopeId, string userReference);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <returns></returns>
+    Task<bool> IsRejected(int envelopeId, string? userReference = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <param name="referenceType"></param>
+    /// <param name="status"></param>
+    /// <param name="withSender"></param>
+    /// <param name="withReceiver"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeHistoryDto>> ReadAsync(int? envelopeId = null, string? userReference = null, ReferenceType? referenceType = null, EnvelopeStatus? status = null, bool withSender = false, bool withReceiver = false);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeHistoryDto>> ReadRejectedAsync(int envelopeId, string? userReference = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <returns></returns>
+    Task<IEnumerable<ReceiverReadDto>> ReadRejectingReceivers(int envelopeId);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <param name="status"></param>
+    /// <param name="comment"></param>
+    /// <returns></returns>
+    Task<DataResult<long>> RecordAsync(int envelopeId, string userReference, EnvelopeStatus status, string? comment = null);
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeMailService.cs

@@ -0,0 +1,45 @@
+using DigitalData.Core.Abstraction.Application.DTO;
+using DigitalData.EmailProfilerDispatcher.Abstraction.Contracts;
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+using EnvelopeGenerator.Domain;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeMailService : IEmailOutService
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverDto"></param>
+    /// <param name="tempType"></param>
+    /// <param name="optionalPlaceholders"></param>
+    /// <returns></returns>
+    Task<DataResult<int>> SendAsync(EnvelopeReceiverDto envelopeReceiverDto, Constants.EmailTemplateType tempType, Dictionary<string, object>? optionalPlaceholders = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="dto"></param>
+    /// <param name="optionalPlaceholders"></param>
+    /// <returns></returns>
+    Task<DataResult<int>> SendAsync(EnvelopeReceiverReadOnlyDto dto, Dictionary<string, object>? optionalPlaceholders = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverDto"></param>
+    /// <returns></returns>
+    Task<DataResult<int>> SendAccessCodeAsync(EnvelopeReceiverDto envelopeReceiverDto);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverDto"></param>
+    /// <returns></returns>
+    Task<DataResult<int>> SendTFAQrCodeAsync(EnvelopeReceiverDto envelopeReceiverDto);
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeReceiverReadOnlyService.cs

@@ -0,0 +1,13 @@
+using DigitalData.Core.Abstraction.Application;
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeReceiverReadOnlyService : ICRUDService<EnvelopeReceiverReadOnlyCreateDto, EnvelopeReceiverReadOnlyDto, EnvelopeReceiverReadOnly, long>
+{
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeReceiverService.cs

@@ -0,0 +1,148 @@
+using CommandDotNet;
+using DigitalData.Core.Abstraction.Application;
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+using EnvelopeGenerator.Application.DTOs.Messaging;
+using EnvelopeGenerator.Application.Envelopes;
+using EnvelopeGenerator.Application.Receivers.Queries.Read;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeReceiverService : IBasicCRUDService<EnvelopeReceiverDto, EnvelopeReceiver, (int Envelope, int Receiver)>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+
+    Task<DataResult<IEnumerable<EnvelopeReceiverDto>>> ReadByUuidAsync(string uuid, bool withEnvelope = true, bool withReceiver = false, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <returns></returns>
+    Task<DataResult<IEnumerable<string?>>> ReadAccessCodeByUuidAsync(string uuid, bool withEnvelope = false, bool withReceiver = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="signature"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<DataResult<IEnumerable<EnvelopeReceiverDto>>> ReadBySignatureAsync(string signature, bool withEnvelope = false, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<DataResult<EnvelopeReceiverDto>> ReadByUuidSignatureAsync(string uuid, string signature, bool withEnvelope = true, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<DataResult<EnvelopeReceiverSecretDto>> ReadWithSecretByUuidSignatureAsync(string uuid, string signature, bool withEnvelope = true, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverId"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<DataResult<EnvelopeReceiverDto>> ReadByEnvelopeReceiverIdAsync(string envelopeReceiverId, bool withEnvelope = true, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="receiverId"></param>
+    /// <returns></returns>
+    Task<DataResult<string>> ReadAccessCodeByIdAsync(int envelopeId, int receiverId);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <param name="accessCode"></param>
+    /// <returns></returns>
+    Task<DataResult<bool>> VerifyAccessCodeAsync(string uuid, string signature, string accessCode);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverId"></param>
+    /// <param name="accessCode"></param>
+    /// <returns></returns>
+    [Command("verify-access-code-async-by-id")]
+    Task<DataResult<bool>> VerifyAccessCodeAsync(string envelopeReceiverId, string accessCode);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverId"></param>
+    /// <returns></returns>
+    Task<DataResult<bool>> IsExisting(string envelopeReceiverId);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="username"></param>
+    /// <param name="min_status"></param>
+    /// <param name="max_status"></param>
+    /// <param name="envelopeQuery"></param>
+    /// <param name="receiverQuery"></param>
+    /// <param name="ignore_statuses"></param>
+    /// <returns></returns>
+    Task<DataResult<IEnumerable<EnvelopeReceiverDto>>> ReadByUsernameAsync(string username, int? min_status = null, int? max_status = null, EnvelopeQuery? envelopeQuery = null, ReadReceiverQuery? receiverQuery = null, params int[] ignore_statuses);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="mail"></param>
+    /// <param name="id"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<DataResult<string>> ReadLastUsedReceiverNameByMailAsync(string? mail = null, int? id = null, string? signature = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverId"></param>
+    /// <param name="message"></param>
+    /// <returns></returns>
+    Task<DataResult<SmsResponse>> SendSmsAsync(string envelopeReceiverId, string message);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <returns></returns>
+    Task<DataResult<IEnumerable<EnvelopeReceiverSecretDto>>> ReadWithSecretByUuidAsync(string uuid);
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeService.cs

@@ -0,0 +1,44 @@
+using DigitalData.Core.Abstraction.Application;
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeService : IBasicCRUDService<EnvelopeDto, Envelope, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="documents"></param>
+    /// <param name="history"></param>
+    /// <param name="documentReceiverElement"></param>
+    /// <returns></returns>
+    Task<DataResult<IEnumerable<EnvelopeDto>>> ReadAllWithAsync(bool documents = false, bool history = false, bool documentReceiverElement = false);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="withDocuments"></param>
+    /// <param name="withHistory"></param>
+    /// <param name="withDocumentReceiverElement"></param>
+    /// <param name="withUser"></param>
+    /// <param name="withAll"></param>
+    /// <returns></returns>
+    Task<DataResult<EnvelopeDto>> ReadByUuidAsync(string uuid, bool withDocuments = false, bool withHistory = false, bool withDocumentReceiverElement = false, bool withUser = false, bool withAll = false);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userId"></param>
+    /// <param name="min_status"></param>
+    /// <param name="max_status"></param>
+    /// <param name="ignore_statuses"></param>
+    /// <returns></returns>
+    Task<DataResult<IEnumerable<EnvelopeDto>>> ReadByUserAsync(int userId, int? min_status = null, int? max_status = null, params int[] ignore_statuses);
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeSmsHandler.cs

@@ -0,0 +1,26 @@
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+using EnvelopeGenerator.Application.DTOs.Messaging;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IEnvelopeSmsHandler
+{
+    /// <summary>
+    /// If expiration is passed then, sends sms and returns smsResponse and up-to-date expiration; otherwise send expiration.
+    /// </summary>
+    /// <param name="er_secret"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    Task<(SmsResponse? SmsResponse, DateTime Expiration)> SendTotpAsync(EnvelopeReceiverSecretDto er_secret, CancellationToken cToken = default);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="totpCode"></param>
+    /// <param name="secretKey"></param>
+    /// <returns></returns>
+    bool VerifyTotp(string totpCode, string secretKey);
+}

EnvelopeGenerator.Application/Contracts/Services/IEnvelopeTypeService.cs

@@ -0,0 +1,13 @@
+using DigitalData.Core.Abstraction.Application;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IEnvelopeTypeService : IBasicCRUDService<EnvelopeTypeDto, EnvelopeType, int>
+{
+}

EnvelopeGenerator.Application/Contracts/Services/IReceiverService.cs

@@ -0,0 +1,29 @@
+using DigitalData.Core.Abstraction.Application;
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IReceiverService : ICRUDService<ReceiverCreateDto, ReceiverReadDto, Receiver, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="emailAddress"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<DataResult<ReceiverReadDto>> ReadByAsync(string? emailAddress = null, string? signature = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="emailAddress"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<Result> DeleteByAsync(string? emailAddress = null, string? signature = null);
+}

EnvelopeGenerator.Application/Contracts/Services/ISmsSender.cs

@@ -0,0 +1,23 @@
+using EnvelopeGenerator.Application.DTOs.Messaging;
+
+namespace EnvelopeGenerator.Application.Contracts.Services;
+
+//TODO: move to DigitalData.Core
+/// <summary>
+/// 
+/// </summary>
+public interface ISmsSender
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    string ServiceProvider { get; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="recipient"></param>
+    /// <param name="message"></param>
+    /// <returns></returns>
+    Task<SmsResponse> SendSmsAsync(string recipient, string message);
+}

EnvelopeGenerator.Application/DTOs/ConfigDto.cs

@@ -0,0 +1,30 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing configuration settings.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class ConfigDto
+{
+    /// <summary>
+    /// Gets or sets the sending profile identifier.
+    /// </summary>
+    public int SendingProfile { get; set; }
+
+    /// <summary>
+    /// Gets or sets the signature host URL or name.
+    /// </summary>
+    public required string SignatureHost { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the external program.
+    /// </summary>
+    public string? ExternalProgramName { get; set; }
+
+    /// <summary>
+    /// Gets or sets the path where exports will be saved.
+    /// </summary>
+    public string? ExportPath { get; set; }
+}

EnvelopeGenerator.Application/DTOs/DocumentReceiverElementDto.cs

@@ -0,0 +1,95 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a positioned element assigned to a document receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class DocumentReceiverElementDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the element.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the identifier of the associated document.
+    /// </summary>
+    public int DocumentId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the identifier of the receiver.
+    /// </summary>
+    public int ReceiverId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the type of the element.
+    /// </summary>
+    public int ElementType { get; set; }
+
+    /// <summary>
+    /// Gets or sets the X coordinate of the element.
+    /// </summary>
+    public double X { get; set; }
+
+    /// <summary>
+    /// Gets or sets the Y coordinate of the element.
+    /// </summary>
+    public double Y { get; set; }
+
+    /// <summary>
+    /// Gets or sets the width of the element.
+    /// </summary>
+    public double Width { get; set; }
+
+    /// <summary>
+    /// Gets or sets the height of the element.
+    /// </summary>
+    public double Height { get; set; }
+
+    /// <summary>
+    /// Gets or sets the page number where the element appears.
+    /// </summary>
+    public int Page { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the element is required.
+    /// </summary>
+    public bool Required { get; set; }
+
+    /// <summary>
+    /// Gets or sets the tooltip text for the element.
+    /// </summary>
+    public string? Tooltip { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the element is read-only.
+    /// </summary>
+    public bool ReadOnly { get; set; }
+
+    /// <summary>
+    /// Gets or sets the annotation index for ordering or reference.
+    /// </summary>
+    public int AnnotationIndex { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the element was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the element was last changed, if applicable.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the top position of the element (in layout terms).
+    /// </summary>
+    public double Top { get; set; }
+
+    /// <summary>
+    /// Gets or sets the left position of the element (in layout terms).
+    /// </summary>
+    public double Left { get; set; }
+}

EnvelopeGenerator.Application/DTOs/DocumentStatusDto.cs

@@ -0,0 +1,50 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing the status of a document for a specific receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class DocumentStatusDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the document status entry.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the ID of the associated envelope.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the ID of the receiver associated with this status.
+    /// </summary>
+    public int ReceiverId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the current status code.
+    /// </summary>
+    public int Status { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the status was changed.
+    /// </summary>
+    public DateTime? StatusChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this record was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this record was last changed.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the display value associated with the status.
+    /// </summary>
+    public string? Value { get; set; }
+}

EnvelopeGenerator.Application/DTOs/EmailTemplateDto.cs

@@ -0,0 +1,31 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    [ApiExplorerSettings(IgnoreApi = true)]
+    public record EmailTemplateDto
+    {
+        /// <summary>
+        /// 
+        /// </summary>
+        public int Id{ get; init; }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public required string Name { get; init; }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public required string Body { get; set; }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public required string Subject { get; set; }
+    };
+}

EnvelopeGenerator.Application/DTOs/EnvelopeCertificateDto.cs

@@ -0,0 +1,50 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing certificate information for an envelope.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeCertificateDto
+{
+    /// <summary>
+    /// Gets the unique identifier of the certificate.
+    /// </summary>
+    public int Id { get; init; }
+
+    /// <summary>
+    /// Gets the envelope ID associated with the certificate.
+    /// </summary>
+    public int EnvelopeId { get; init; }
+
+    /// <summary>
+    /// Gets the UUID of the envelope.
+    /// </summary>
+    public string EnvelopeUuid { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Gets the subject of the envelope.
+    /// </summary>
+    public string EnvelopeSubject { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Gets the ID of the creator of the envelope.
+    /// </summary>
+    public int CreatorId { get; init; }
+
+    /// <summary>
+    /// Gets the name of the creator.
+    /// </summary>
+    public string CreatorName { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Gets the email address of the creator.
+    /// </summary>
+    public string CreatorEmail { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Gets the current status of the envelope.
+    /// </summary>
+    public int EnvelopeStatus { get; init; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeDocumentDto.cs

@@ -0,0 +1,35 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a document within an envelope, including optional binary data and form elements.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeDocumentDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the document.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the envelope ID to which the document belongs.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the date and time when the document was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the binary data of the document, if available.
+    /// </summary>
+    public byte[]? ByteData { get; set; }
+
+    /// <summary>
+    /// Gets or sets the collection of elements associated with the document for receiver interactions, if any.
+    /// </summary>
+    public IEnumerable<DocumentReceiverElementDto>? Elements { get; set; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeDto.cs

@@ -0,0 +1,120 @@
+using DigitalData.EmailProfilerDispatcher.Abstraction.Attributes;
+using DigitalData.UserManager.Application.DTOs.User;
+using EnvelopeGenerator.Domain.Entities;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeDto
+{
+	/// <summary>
+	/// 
+	/// </summary>
+	public int Id { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int UserId { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int Status { get; set; }
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    public string StatusName { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    public string Uuid { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    [TemplatePlaceholder("[MESSAGE]")]
+    public string Message { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    [TemplatePlaceholder("[DOCUMENT_TITLE]")]
+    public string Title { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int? ContractType { get; set; }
+
+    /// <summary>
+    /// Default value is 'de-DE'
+    /// </summary>
+    public string Language { get; set; } = "de-DE";
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int? EnvelopeTypeId { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int? CertificationType { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool? UseAccessCode { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool TFAEnabled { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public UserReadDto? User { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public EnvelopeType? EnvelopeType { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? EnvelopeTypeTitle { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool IsAlreadySent { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public byte[]? DocResult { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public IEnumerable<EnvelopeDocumentDto>? Documents { get; set; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeHistory/EnvelopeHistoryCreateDto.cs

@@ -0,0 +1,34 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeHistory;
+
+/// <summary>
+/// Data Transfer Object for creating a new envelope history record.
+/// </summary>
+public class EnvelopeHistoryCreateDto
+{
+    /// <summary>
+    /// Gets or sets the identifier of the envelope.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the user reference associated with the action.
+    /// </summary>
+    public required string UserReference { get; set; }
+
+    /// <summary>
+    /// Gets or sets the status of the envelope at the time of the action.
+    /// </summary>
+    public int Status { get; set; }
+
+    /// <summary>
+    /// Gets or sets the date and time when the action occurred.
+    /// </summary>
+    public DateTime? ActionDate { get; set; }
+
+    /// <summary>
+    /// Gets or sets an optional comment related to the action.
+    /// </summary>
+    public string? Comment { get; set; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeHistory/EnvelopeHistoryDto.cs

@@ -0,0 +1,69 @@
+using DigitalData.UserManager.Application.DTOs.User;
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using static EnvelopeGenerator.Domain.Constants;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeHistory;
+
+/// <summary>
+/// Data Transfer Object representing the history of an envelope, including status, sender, receiver, and related metadata.
+/// </summary>
+public record EnvelopeHistoryDto
+{
+    /// <summary>
+    /// Unique identifier for the envelope history entry.
+    /// </summary>
+    public long Id { get; set; }
+
+    /// <summary>
+    /// Identifier of the associated envelope.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Reference string for the user related to this history entry.
+    /// </summary>
+    public required string UserReference { get; set; }
+
+    /// <summary>
+    /// Status code of the envelope at this history point.
+    /// </summary>
+    public int Status { get; set; }
+
+    /// <summary>
+    /// Human-readable name of the status.
+    /// </summary>
+    public string? StatusName { get; set; }
+
+    /// <summary>
+    /// Date and time when this history entry was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Date and time when an action was performed, if applicable.
+    /// </summary>
+    public DateTime? ActionDate { get; set; }
+
+    /// <summary>
+    /// Information about the sender associated with this history entry.
+    /// </summary>
+    public UserCreateDto? Sender { get; set; }
+
+    /// <summary>
+    /// Information about the receiver associated with this history entry.
+    /// </summary>
+    public ReceiverReadDto? Receiver { get; set; }
+
+    /// <summary>
+    /// Type of reference for this history entry.
+    /// </summary>
+    public ReferenceType ReferenceType { get; set; }
+
+    /// <summary>
+    /// Optional comment related to this history entry.
+    /// </summary>
+    public string? Comment { get; set; }
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => Id.GetHashCode();
+};

EnvelopeGenerator.Application/DTOs/EnvelopeReceiver/EnvelopeReceiverBasicDto.cs

@@ -0,0 +1,67 @@
+using DigitalData.EmailProfilerDispatcher.Abstraction.Attributes;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeReceiverBasicDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public (int Envelope, int Receiver) Id => (Envelope: EnvelopeId, Receiver: ReceiverId);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int EnvelopeId { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int ReceiverId { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int Sequence { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [TemplatePlaceholder("[NAME_RECEIVER]")]
+    public string? Name { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? JobTitle { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? CompanyName { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? PrivateMessage { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime? ChangedWhen { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool HasPhoneNumber { get; init; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeReceiver/EnvelopeReceiverDto.cs

@@ -0,0 +1,22 @@
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+
+/// <summary>
+/// 
+/// </summary>
+
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeReceiverDto() : EnvelopeReceiverBasicDto()
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public EnvelopeDto? Envelope { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public ReceiverReadDto? Receiver { get; set; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeReceiver/EnvelopeReceiverSecretDto.cs

@@ -0,0 +1,20 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeReceiverSecretDto : EnvelopeReceiverDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? AccessCode { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? PhoneNumber { get; init; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyCreateDto.cs

@@ -0,0 +1,39 @@
+using Microsoft.AspNetCore.Mvc;
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// 
+/// </summary>
+/// <param name="DateValid"></param>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeReceiverReadOnlyCreateDto(
+    DateTime DateValid)
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    [EmailAddress]
+    [Required]
+    public required string ReceiverMail { get; init; }
+
+    /// <summary>
+    /// Default value is null
+    /// </summary>
+    [JsonIgnore]
+    public long? EnvelopeId { get; set; } = null;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonIgnore]
+    public string? AddedWho { get; set; }
+
+    /// <summary>
+    /// Default value is DateTime.Now
+    /// </summary>
+    [JsonIgnore]
+    public DateTime AddedWhen { get; } = DateTime.Now;
+};

EnvelopeGenerator.Application/DTOs/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyDto.cs

@@ -0,0 +1,63 @@
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// Represents a read-only Data Transfer Object (DTO) for an envelope receiver.
+/// Contains information about the receiver, associated envelope, and audit details.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeReceiverReadOnlyDto
+{
+    /// <summary>
+    /// Gets or inits the unique identifier of the envelope receiver.
+    /// </summary>
+    public long Id { get; init; }
+
+    /// <summary>
+    /// Gets or inits the identifier of the associated envelope.
+    /// </summary>
+    public long EnvelopeId { get; init; }
+
+    /// <summary>
+    /// Gets or inits the email address of the receiver.
+    /// </summary>
+    public required string ReceiverMail { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date until which the receiver is valid.
+    /// </summary>
+    public DateTime DateValid { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date and time when the receiver was added.
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+
+    /// <summary>
+    /// Gets or inits the user who added the receiver.
+    /// Default value is 'unknown'.
+    /// </summary>
+    public string AddedWho { get; init; } = "Unknown";
+
+    /// <summary>
+    /// Gets or inits the associated envelope details.
+    /// </summary>
+    public EnvelopeDto? Envelope { get; set; }
+
+    /// <summary>
+    /// Gets or inits the user who last changed the receiver, if any.
+    /// </summary>
+    public string? ChangedWho { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date and time when the receiver was last changed, if any.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or inits the associated receiver details.
+    /// </summary>
+    public ReceiverReadDto? Receiver { get; set; }
+}

EnvelopeGenerator.Application/DTOs/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyUpdateDto.cs

@@ -0,0 +1,31 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// Data Transfer Object for updating a read-only envelope receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeReceiverReadOnlyUpdateDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the envelope receiver.
+    /// </summary>
+    public long Id { get; init; }
+
+    /// <summary>
+    /// Gets or sets the date when the envelope receiver becomes valid.
+    /// </summary>
+    public DateTime DateValid { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the user who made the change.
+    /// Default value is unknown.
+    /// </summary>
+    public string ChangedWho { get; set; } = "Unknown";
+
+    /// <summary>
+    /// Gets or sets the date and time when the change was made.
+    /// </summary>
+    public DateTime ChangedWhen { get; set; } = DateTime.Now;
+}

EnvelopeGenerator.Application/DTOs/EnvelopeTypeDto.cs

@@ -0,0 +1,85 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a type of envelope with its configuration settings.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeTypeDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the envelope type.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the title of the envelope type.
+    /// </summary>
+    public string Title { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the language code used in this envelope type.
+    /// </summary>
+    public string Language { get; set; } = "de-DE";
+
+    /// <summary>
+    /// Gets or sets the number of days after which the envelope expires.
+    /// </summary>
+    public int? ExpiresDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the certification type identifier.
+    /// </summary>
+    public int? CertificationType { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether an access code is required.
+    /// </summary>
+    public bool? UseAccessCode { get; set; }
+
+    /// <summary>
+    /// Gets or sets the final email template ID to be sent to the creator.
+    /// </summary>
+    public int? FinalEmailToCreator { get; set; }
+
+    /// <summary>
+    /// Gets or sets the final email template ID to be sent to the receivers.
+    /// </summary>
+    public int? FinalEmailToReceivers { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this envelope type was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this envelope type was last changed.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of days before expiry when a warning should be sent.
+    /// </summary>
+    public int? ExpiresWarningDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether reminder emails should be sent.
+    /// </summary>
+    public bool? SendReminderEmails { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of days before the first reminder is sent.
+    /// </summary>
+    public int? FirstReminderDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the interval in days between reminder emails.
+    /// </summary>
+    public int? ReminderIntervalDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the contract type associated with the envelope type.
+    /// </summary>
+    public int? ContractType { get; set; }
+}

EnvelopeGenerator.Application/DTOs/MappingProfile.cs

@@ -0,0 +1,68 @@
+using AutoMapper;
+using EnvelopeGenerator.Application.DTOs.EnvelopeHistory;
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
+using EnvelopeGenerator.Application.DTOs.Messaging;
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using EnvelopeGenerator.Application.Extensions;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Represents the AutoMapper profile configuration for mapping between
+/// domain entities and data transfer objects (DTOs) used within the EnvelopeGenerator application.
+/// </summary>
+public class MappingProfile : Profile
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="MappingProfile"/> class.
+    /// Configures the mappings between entities and DTOs used throughout the application.
+    /// </summary>
+    public MappingProfile()
+    {
+        // Entity to DTO mappings
+        CreateMap<Config, ConfigDto>();
+        CreateMap<DocumentReceiverElement, DocumentReceiverElementDto>();
+        CreateMap<DocumentStatus, DocumentStatusDto>();
+        CreateMap<EmailTemplate, EmailTemplateDto>();
+        CreateMap<Envelope, EnvelopeDto>();
+        CreateMap<EnvelopeCertificate, EnvelopeCertificateDto>();
+        CreateMap<EnvelopeDocument, EnvelopeDocumentDto>();
+        CreateMap<Domain.Entities.EnvelopeHistory, EnvelopeHistoryDto>();
+        CreateMap<Domain.Entities.EnvelopeHistory, EnvelopeHistoryCreateDto>();
+        CreateMap<Domain.Entities.EnvelopeReceiver, EnvelopeReceiverDto>();
+        CreateMap<Domain.Entities.EnvelopeReceiver, EnvelopeReceiverSecretDto>();
+        CreateMap<EnvelopeType, EnvelopeTypeDto>();
+        CreateMap<Domain.Entities.Receiver, ReceiverReadDto>();
+        CreateMap<Domain.Entities.Receiver, ReceiverCreateDto>();
+        CreateMap<Domain.Entities.Receiver, ReceiverUpdateDto>();
+        CreateMap<Domain.Entities.EnvelopeReceiverReadOnly, EnvelopeReceiverReadOnlyDto>();
+
+        // DTO to Entity mappings
+        CreateMap<ConfigDto, Config>();
+        CreateMap<DocumentReceiverElementDto, DocumentReceiverElement>();
+        CreateMap<DocumentStatusDto, DocumentStatus>();
+        CreateMap<EmailTemplateDto, EmailTemplate>();
+        CreateMap<EnvelopeDto, Envelope>();
+        CreateMap<EnvelopeCertificateDto, EnvelopeCertificate>();
+        CreateMap<EnvelopeDocumentDto, EnvelopeDocument>();
+        CreateMap<EnvelopeHistoryDto, Domain.Entities.EnvelopeHistory>();
+        CreateMap<EnvelopeHistoryCreateDto, Domain.Entities.EnvelopeHistory>();
+        CreateMap<EnvelopeReceiverDto, Domain.Entities.EnvelopeReceiver>();
+        CreateMap<EnvelopeTypeDto, EnvelopeType>();
+        CreateMap<ReceiverReadDto, Domain.Entities.Receiver>().ForMember(rcv => rcv.EnvelopeReceivers, rcvReadDto => rcvReadDto.Ignore());
+        CreateMap<ReceiverCreateDto, Domain.Entities.Receiver>();
+        CreateMap<ReceiverUpdateDto, Domain.Entities.Receiver>();
+        CreateMap<EnvelopeReceiverBase, EnvelopeReceiverBasicDto>();
+        CreateMap<EnvelopeReceiverReadOnlyCreateDto, Domain.Entities.EnvelopeReceiverReadOnly>();
+        CreateMap<EnvelopeReceiverReadOnlyUpdateDto, Domain.Entities.EnvelopeReceiverReadOnly>();
+
+        // Messaging mappings
+        // for GTX messaging
+        CreateMap<GtxMessagingResponse, SmsResponse>()
+            .ConstructUsing(gtxRes => gtxRes.Ok()
+                ? new SmsResponse() { Ok = true }
+                : new SmsResponse() { Ok = false, Errors = gtxRes });
+    }
+}

EnvelopeGenerator.Application/DTOs/Messaging/GtxMessagingResponse.cs

@@ -0,0 +1,9 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.Messaging;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class GtxMessagingResponse : Dictionary<string, object?> { }

EnvelopeGenerator.Application/DTOs/Messaging/SmsResponse.cs

@@ -0,0 +1,25 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.Messaging;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record SmsResponse
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public required bool Ok { get; init; }
+
+    /// <summary>
+    /// Returns !Ok
+    /// </summary>
+    public bool Failed => !Ok;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public dynamic? Errors { get; init; }
+}

EnvelopeGenerator.Application/DTOs/Receiver/ReceiverCreateDto.cs

@@ -0,0 +1,53 @@
+using Microsoft.AspNetCore.Mvc;
+using System.ComponentModel.DataAnnotations;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace EnvelopeGenerator.Application.DTOs.Receiver;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record ReceiverCreateDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public ReceiverCreateDto()
+    {
+        _sha256HexOfMail = new(() =>
+        {
+            var bytes_arr = Encoding.UTF8.GetBytes(EmailAddress!.ToUpper());
+            var hash_arr = SHA256.HashData(bytes_arr);
+            var hexa_str = BitConverter.ToString(hash_arr);
+            return hexa_str.Replace("-", string.Empty);
+        });
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [EmailAddress]
+    public required string EmailAddress { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? TotpSecretkey { get; init; }
+
+    /// <summary>
+    /// var bytes_arr = Encoding.UTF8.GetBytes(EmailAddress.ToUpper());<br/>
+    /// var hash_arr = SHA256.HashData(bytes_arr);
+    /// var hexa_str = BitConverter.ToString(hash_arr);
+    /// return hexa_str.Replace("-", string.Empty);
+    /// </summary>
+    public string Signature => _sha256HexOfMail.Value;
+
+    private readonly Lazy<string> _sha256HexOfMail;
+
+    /// <summary>
+    /// Default value is DateTime.Now
+    /// </summary>
+    public DateTime AddedWhen { get; } = DateTime.Now;
+};

EnvelopeGenerator.Application/DTOs/Receiver/ReceiverReadDto.cs

@@ -0,0 +1,62 @@
+using EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
+using Microsoft.AspNetCore.Mvc;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.Application.DTOs.Receiver;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class ReceiverReadDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public required string EmailAddress { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public required string Signature { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonIgnore]
+    public IEnumerable<EnvelopeReceiverBasicDto>? EnvelopeReceivers { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? LastUsedName => EnvelopeReceivers?.LastOrDefault()?.Name;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? TotpSecretkey { get; set; } = null;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime? TfaRegDeadline { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    public override int GetHashCode()
+    {
+        return Id.GetHashCode();
+    }
+}

EnvelopeGenerator.Application/DTOs/Receiver/ReceiverUpdateDto.cs

@@ -0,0 +1,27 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.DTOs.Receiver;
+
+/// <summary>
+/// Data Transfer Object for updating a receiver's information.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class ReceiverUpdateDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the receiver.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the TOTP (Time-based One-Time Password) secret key.
+    /// Optional.
+    /// </summary>
+    public string? TotpSecretkey { get; set; }
+
+    /// <summary>
+    /// Gets or sets the deadline for two-factor authentication registration.
+    /// Optional.
+    /// </summary>
+    public DateTime? TfaRegDeadline { get; set; }
+}

EnvelopeGenerator.Application/DependencyInjection.cs

@@ -0,0 +1,67 @@
+using EnvelopeGenerator.Application.Configurations;
+using EnvelopeGenerator.Application.Services;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using DigitalData.Core.Client;
+using QRCoder;
+using EnvelopeGenerator.Application.Contracts.Services;
+using System.Reflection;
+using EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+
+namespace EnvelopeGenerator.Application;
+
+/// <summary>
+/// Extensions method for dependency injection
+/// </summary>
+public static class DependencyInjection
+{
+    /// <summary>
+    /// Adds all required services for envelope generator application
+    /// </summary>
+    /// <param name="services"></param>
+    /// <param name="config"></param>
+    /// <returns></returns>
+    [Obsolete("Use MediatR")]
+    public static IServiceCollection AddEnvelopeGeneratorServices(this IServiceCollection services, IConfiguration config)
+    {
+        //Inject CRUD Service and repositoriesad
+        services.TryAddScoped<IConfigService, ConfigService>();
+        services.TryAddScoped<IDocumentReceiverElementService, DocumentReceiverElementService>();
+        services.TryAddScoped<IEnvelopeDocumentService, EnvelopeDocumentService>();
+        services.TryAddScoped<IEnvelopeHistoryService, EnvelopeHistoryService>();
+        services.TryAddScoped<IDocumentStatusService, DocumentStatusService>();
+        services.TryAddScoped<IEmailTemplateService, EmailTemplateService>();
+        services.TryAddScoped<IEnvelopeService, EnvelopeService>();
+        services.TryAddScoped<IEnvelopeCertificateService, EnvelopeCertificateService>();
+        services.TryAddScoped<IEnvelopeDocumentService, EnvelopeDocumentService>();
+        services.TryAddScoped<IEnvelopeReceiverService, EnvelopeReceiverService>();
+        services.TryAddScoped<IEnvelopeTypeService, EnvelopeTypeService>();
+        services.TryAddScoped<IReceiverService, ReceiverService>();
+        services.TryAddScoped<IEnvelopeReceiverReadOnlyService, EnvelopeReceiverReadOnlyService>();
+
+        //Auto mapping profiles
+        services.AddAutoMapper(Assembly.GetExecutingAssembly());
+        services.AddAutoMapper(typeof(DigitalData.UserManager.Application.DIExtensions));
+
+        services.Configure<DispatcherParams>(config.GetSection(nameof(DispatcherParams)));
+        services.Configure<MailParams>(config.GetSection(nameof(MailParams)));
+        services.Configure<AuthenticatorParams>(config.GetSection(nameof(AuthenticatorParams)));
+        services.Configure<TotpSmsParams>(config.GetSection(nameof(TotpSmsParams)));
+        services.Configure<DbTriggerParams>(config.GetSection(nameof(DbTriggerParams)));
+
+        services.AddHttpClientService<GtxMessagingParams>(config.GetSection(nameof(GtxMessagingParams)));
+        services.TryAddSingleton<ISmsSender, GTXSmsSender>();
+        services.TryAddSingleton<IEnvelopeSmsHandler, EnvelopeSmsHandler>();
+        services.TryAddSingleton<IAuthenticator, Authenticator>();
+        services.TryAddSingleton<QRCodeGenerator>();
+
+        services.AddMediatR(cfg =>
+        {
+            cfg.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly());
+            cfg.RegisterServicesFromAssembly(typeof(CreateEnvelopeReceiverCommandHandler).Assembly);
+        });
+
+        return services;
+    }
+}

EnvelopeGenerator.Application/Documents/Queries/Read/ReadDocumentMappingProfile.cs

@@ -0,0 +1,18 @@
+using AutoMapper;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Documents.Queries.Read;
+
+/// <summary>
+/// 
+/// </summary>
+public class ReadDocumentMappingProfile : Profile
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public ReadDocumentMappingProfile()
+    {
+        CreateMap<EnvelopeDocument, ReadDocumentResponse>();
+    }
+}

EnvelopeGenerator.Application/Documents/Queries/Read/ReadDocumentQuery.cs

@@ -0,0 +1,12 @@
+using MediatR;
+
+namespace EnvelopeGenerator.Application.Documents.Queries.Read;
+
+/// <summary>
+/// Represents a query to read a document based on its unique identifier or associated envelope identifier.
+/// </summary>
+/// <param name="Id">The unique identifier of the document. Optional.</param>
+/// <param name="EnvelopeId">The identifier of the envelope associated with the document. Optional.</param>
+public record ReadDocumentQuery(int? Id = null, int? EnvelopeId = null) : IRequest<ReadDocumentResponse?>
+{
+}

EnvelopeGenerator.Application/Documents/Queries/Read/ReadDocumentQueryHandler.cs

@@ -0,0 +1,48 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.Documents.Queries.Read;
+
+/// <summary>
+/// Handles queries for reading <see cref="EnvelopeDocument"/> data based on either the document ID or the envelope ID.
+/// </summary>
+public class ReadDocumentQueryHandler : IRequestHandler<ReadDocumentQuery, ReadDocumentResponse?>
+{
+    /// <summary>
+    /// Repository for accessing <see cref="EnvelopeDocument"/> entities.
+    /// </summary>
+    private readonly IRepository<EnvelopeDocument> _repo;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ReadDocumentQueryHandler"/> class.
+    /// </summary>
+    /// <param name="envelopeDocumentRepository">The repository used to access <see cref="EnvelopeDocument"/> entities.</param>
+    public ReadDocumentQueryHandler(IRepository<EnvelopeDocument> envelopeDocumentRepository)
+    {
+        _repo = envelopeDocumentRepository;
+    }
+
+    /// <summary>
+    /// Handles the <see cref="ReadDocumentQuery"/> and returns a <see cref="ReadDocumentResponse"/> based on the provided identifiers.
+    /// </summary>
+    /// <param name="query">The query containing the document ID or envelope ID to search for.</param>
+    /// <param name="cancellationToken">A token to monitor for cancellation requests.</param>
+    /// <returns>
+    /// A <see cref="ReadDocumentResponse"/> if a matching document is found; otherwise, <c>null</c>.
+    /// </returns>
+    /// <exception cref="InvalidOperationException">
+    /// Thrown when neither <see cref="ReadDocumentQuery.Id"/> nor <see cref="ReadDocumentQuery.EnvelopeId"/> is provided.
+    /// </exception>
+    [Obsolete("Use MediatR")]
+    public async Task<ReadDocumentResponse?> Handle(ReadDocumentQuery query, CancellationToken cancellationToken)
+    {
+        if (query.Id is not null)
+            return await _repo.ReadOrDefaultAsync<ReadDocumentResponse>(d => d.Id == query.Id);
+        else if (query.EnvelopeId is not null)
+            return await _repo.ReadOrDefaultAsync<ReadDocumentResponse>(d => d.EnvelopeId == query.EnvelopeId);
+
+        throw new InvalidOperationException(
+            $"Invalid {nameof(ReadDocumentQuery)}: either {nameof(query.Id)} or {nameof(query.EnvelopeId)} must be provided.");
+    }
+}

EnvelopeGenerator.Application/Documents/Queries/Read/ReadDocumentResponse.cs

@@ -0,0 +1,12 @@
+namespace EnvelopeGenerator.Application.Documents.Queries.Read;
+
+/// <summary>
+/// Represents the response for reading a document.
+/// </summary>
+public class ReadDocumentResponse : ReadDocumentResponseBase
+{
+    /// <summary>
+    /// The binary data of the document, if available.
+    /// </summary>
+    public byte[]? ByteData { get; init; }
+}

EnvelopeGenerator.Application/Documents/Queries/Read/ReadDocumentResponseBase.cs

@@ -0,0 +1,22 @@
+namespace EnvelopeGenerator.Application.Documents.Queries.Read;
+
+/// <summary>
+/// Represents the response for reading a document.
+/// </summary>
+public class ReadDocumentResponseBase
+{
+    /// <summary>
+    /// The unique identifier of the document.
+    /// </summary>
+    public int Guid { get; init; }
+
+    /// <summary>
+    /// The identifier of the associated envelope.
+    /// </summary>
+    public int EnvelopeId { get; init; }
+
+    /// <summary>
+    /// The date and time when the document was added.
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+}

EnvelopeGenerator.Application/EmailTemplates/Commands/Reset/ResetEmailTemplateCommand.cs

@@ -0,0 +1,40 @@
+using EnvelopeGenerator.Domain;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Commands.Reset;
+
+/// <summary>
+/// Ein Befehl zum Zurücksetzen einer E-Mail-Vorlage auf die Standardwerte.
+/// Erbt von <see cref="EmailTemplateQuery"/> und ermöglicht die Angabe einer optionalen ID und eines Typs der E-Mail-Vorlage.<br/><br/>
+/// Beispiele:<br/>
+/// 0 - DocumentReceived: Benachrichtigung über den Empfang eines Dokuments.<br/>
+/// 1 - DocumentSigned: Benachrichtigung über die Unterzeichnung eines Dokuments.<br/>
+/// 2 - DocumentDeleted: Benachrichtigung über das Löschen eines Dokuments.<br/>
+/// 3 - DocumentCompleted: Benachrichtigung über den Abschluss eines Dokuments.<br/>
+/// 4 - DocumentAccessCodeReceived: Benachrichtigung über den Erhalt eines Zugangscodes.<br/>
+/// 5 - DocumentShared: Benachrichtigung über das Teilen eines Dokuments.<br/>
+/// 6 - TotpSecret: Benachrichtigung über ein TOTP-Geheimnis.<br/>
+/// 7 - DocumentRejected_ADM (Für den Absender): Mail an den Absender, wenn das Dokument abgelehnt wird.<br/>
+/// 8 - DocumentRejected_REC (Für den ablehnenden Empfänger): Mail an den ablehnenden Empfänger, wenn das Dokument abgelehnt wird.<br/>
+/// 9 - DocumentRejected_REC_2 (Für sonstige Empfänger): Mail an andere Empfänger (Brief), wenn das Dokument abgelehnt wird.<br/>
+/// </summary>
+public record ResetEmailTemplateCommand : EmailTemplateQuery, IRequest
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="orginal"></param>
+    public ResetEmailTemplateCommand(EmailTemplateQuery? orginal = null) : base(orginal ?? new())
+    {
+
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="Id">Die optionale ID der E-Mail-Vorlage, die zurückgesetzt werden soll.</param>
+    /// <param name="Type">Der Typ der E-Mail-Vorlage, z. B. <see cref="Constants.EmailTemplateType"/> (optional).</param>
+    public ResetEmailTemplateCommand(int? Id = null, Constants.EmailTemplateType? Type = null) : base(Id, Type)
+    {
+    }
+};

EnvelopeGenerator.Application/EmailTemplates/Commands/Reset/ResetEmailTemplateCommandHandler.cs

@@ -0,0 +1,114 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Commands.Reset;
+
+/// <summary>
+/// 
+/// </summary>
+public class ResetEmailTemplateCommandHandler : IRequestHandler<ResetEmailTemplateCommand>
+{
+    private readonly IRepository<EmailTemplate> _repository;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="repository"></param>
+    public ResetEmailTemplateCommandHandler(IRepository<EmailTemplate> repository)
+    {
+        _repository = repository;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="cancel"></param>
+    /// <returns></returns>
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    public async Task Handle(ResetEmailTemplateCommand request, CancellationToken cancel)
+    {
+        var temps = request.Id is not null
+            ? await _repository.ReadAllAsync<EmailTemplateDto>(t => t.Id == request.Id, cancel)
+            : request.Type is not null
+                ? await _repository.ReadAllAsync<EmailTemplateDto>(t => t.Name == request.Type.ToString(), cancel)
+                : await _repository.ReadAllAsync<EmailTemplateDto>(cancellation: cancel);
+
+        foreach (var temp in temps)
+        {
+            var def = Defaults.Where(t => t.Name == temp.Name).FirstOrDefault();
+            if(def is not null)
+                await _repository.UpdateAsync(def, t => t.Id == temp.Id, cancel);
+        }
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public static readonly IEnumerable<EmailTemplateDto> Defaults = new List<EmailTemplateDto>()
+    {
+        new(){
+        Id = 1,
+        Name = "DocumentReceived",
+        Body = "Guten Tag [NAME_RECEIVER],<br />\r\n<br /><B><I>\r\n[NAME_SENDER]</I></B> hat Ihnen ein Dokument zum [SIGNATURE_TYPE] gesendet.<br />\r\n<br />\r\nÜber den folgenden Link können Sie das Dokument einsehen und elektronisch unterschreiben: <a href=\"[LINK_TO_DOCUMENT]\">[LINK_TO_DOCUMENT_TEXT]</a><br />\r\n<br />\r\n[MESSAGE]<br />\r\n<br />\r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "Dokument erhalten: '[DOCUMENT_TITLE]'"
+        },
+        new(){
+        Id = 2,
+        Name = "DocumentDeleted",
+        Body = "Guten Tag [NAME_RECEIVER],<br />\r\n<br /><B><I>\r\n[NAME_SENDER]</I></B> hat den Umschlag <B><I>'[DOCUMENT_TITLE]'</I></B> gelöscht/zurückgezogen.<br /><p>\rBegründung: <br /> <I>[REASON]</I> <p>\r\n<br />\r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "Umschlag zurückgezogen: '[DOCUMENT_TITLE]'"
+        },
+        new(){
+        Id = 3,
+        Name = "DocumentSigned",
+        Body = "Guten Tag [NAME_RECEIVER],<br />\r\n<br />\r\nhiermit bestätigen wir Ihnen die erfolgreiche Signatur für den Vorgang <B><I>'[DOCUMENT_TITLE]'</I></B>.<br />\r\nWenn alle Vertragspartner unterzeichnet haben, erhalten Sie ebenfalls per email ein unterschriebenes Exemplar mit dem Signierungszertifikat!\r\n<br />\r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "Dokument unterschrieben: '[DOCUMENT_TITLE]'"
+        },
+        new(){
+        Id = 4,
+        Name = "DocumentCompleted",
+        Body = "Guten Tag [NAME_RECEIVER],<br />\r\n<br />\r\nDer Signaturvorgang <B><I>'[DOCUMENT_TITLE]'</I></B> wurde erfolgreich abgeschlossen.<br />\r\n<br />\r\nSie erhalten das Dokument mit einem detaillierten Ergebnisbericht als Anhang zu dieser EmailAddress.<br />\r\n<br />\r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "Umschlag abgeschlossen: '[DOCUMENT_TITLE]'"
+        },
+        new(){
+        Id = 5,
+        Name = "DocumentAccessCodeReceived",
+        Body = "Guten Tag [NAME_RECEIVER],<br />\r\n<br /><B><I>\r\n[NAME_SENDER]</I></B> hat Ihnen ein Dokument zum [SIGNATURE_TYPE] gesendet. <br />\r\n<br />\r\nVerwenden Sie den folgenden Zugriffscode, um das Dokument einzusehen:<br />\r\n<br />\r\n[DOCUMENT_ACCESS_CODE]<br />\r\n<br />\r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "Zugriffscode für Dokument erhalten: '[DOCUMENT_TITLE]'"
+        },
+        new(){
+        Id = 6,
+        Name = "DocumentRejected_ADM",
+        Body = "Guten Tag [NAME_SENDER],<p><B><I>[NAME_RECEIVER]</I></B> hat den Umschlag <B><I>'[DOCUMENT_TITLE]'</I></B> mit folgendem Grund abgelehnt: <p>\r\n[REASON] \r\n<p>Der Umschlag wurde auf den Status Rejected gesetzt. <p> \r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "'[DOCUMENT_TITLE]' - Unterzeichnungsvorgang zurückgezogen"
+        },
+        new(){
+        Id = 9,
+        Name = "DocumentRejected_REC",
+        Body = "Guten Tag [NAME_RECEIVER],\r\n<p>Hiermit bestätigen wir Ihnen die Ablehnung des Unterzeichnungsvorganges <B><I>'[DOCUMENT_TITLE]'</I></B>!<p>Der Vertragsinhaber <B><I>[NAME_SENDER]</I></B> wurde über die Ablehnung informiert. <p> \r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "'[DOCUMENT_TITLE]' - Bestätigung Ablehnung"
+        },
+        new(){
+        Id = 10,
+        Name = "DocumentRejected_REC_2",
+        Body = "Guten Tag [NAME_RECEIVER],\r\n<p>Der Unterzeichnungsvorganges <B><I>'[DOCUMENT_TITLE]'</I></B> wurde durch einen anderen Vertragspartner abgelehnt! Ihre notwendige Unterzeichnung wurde verworfen.<p> Der Vertragsinhaber <B><I>[NAME_SENDER]</I></B> wird sich bei Bedarf mit Ihnen in Verbindung setzen. <p> \r\nMit freundlichen Grüßen<br />\r\n<br />\r\n[NAME_PORTAL]",
+        Subject = "'[DOCUMENT_TITLE]' - Unterzeichnungsvorgang abgelehnt."
+        },
+        new(){
+        Id = 11,
+        Name = "DocumentShared",
+        Body = "Guten Tag,<br />  <br /><B><I>  [NAME_RECEIVER]</I></B> hat Ihnen ein Dokument zum Ansehen gesendet.<br />  <br />  Über den folgenden Link können Sie das Dokument einsehen: <a href=\"[LINK_TO_DOCUMENT]\">[LINK_TO_DOCUMENT_TEXT]</a><br /> <br />  <br />  Mit freundlichen Grüßen<br />  <br />  [NAME_PORTAL]",
+        Subject = "Dokument geteilt: '[DOCUMENT_TITLE]'"
+        },
+        new(){
+        Id = 12,
+        Name = "TotpSecret",
+        Body = "Guten Tag,<br /> <br />Sie können auf Ihren Zwei-Faktor-Authentifizierungscode zugreifen, indem Sie den unten stehenden QR-Code mit einer beliebigen Authentifizierungs-App auf Ihrem Telefon scannen (Google Authenticator, Microsoft Authenticator usw.). Dieser Code ist bis zum [TFA_EXPIRATION] gültig.<br /> <br /> <img src=\"data:image/png;base64,[TFA_QR_CODE]\" style=\"width: 13rem; height: 13rem;\"><br /> <br />\r\n<br /> Mit freundlichen Grüßen<br /> <br /> [NAME_PORTAL]",
+        Subject = "2-Faktor-Verifizierung QR-Code"
+        }
+    };
+
+}

EnvelopeGenerator.Application/EmailTemplates/Commands/Update/UpdateEmailTemplateCommand.cs

@@ -0,0 +1,29 @@
+using MediatR;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Commands.Update;
+
+
+/// <summary>
+/// Befehl zum Aktualisieren einer E-Mail-Vorlage.
+/// </summary>
+/// <param name="Body">
+/// (Optional)Der neue Inhalt des E-Mail-Textkörpers. Wenn null, bleibt der vorhandene Inhalt unverändert.
+/// </param>
+/// <param name="Subject">
+/// (Optional) Der neue Betreff der E-Mail. Wenn null, bleibt der vorhandene Betreff unverändert.
+/// </param>
+public record UpdateEmailTemplateCommand(string? Body = null, string? Subject = null) : IRequest
+{
+    /// <param>
+    /// Die Abfrage, die die E-Mail-Vorlage darstellt, die aktualisiert werden soll.
+    /// </param>
+    [JsonIgnore]
+    public EmailTemplateQuery? EmailTemplateQuery { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonIgnore]
+    public DateTime ChangedWhen { get; init; } = DateTime.Now;
+}

EnvelopeGenerator.Application/EmailTemplates/Commands/Update/UpdateEmailTemplateCommandHandler.cs

@@ -0,0 +1,65 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Application.Exceptions;
+using EnvelopeGenerator.Domain;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Commands.Update;
+
+/// <summary>
+/// 
+/// </summary>
+public class UpdateEmailTemplateCommandHandler : IRequestHandler<UpdateEmailTemplateCommand>
+{
+    private readonly IRepository<EmailTemplate> _repository;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="repository"></param>
+    public UpdateEmailTemplateCommandHandler(IRepository<EmailTemplate> repository)
+    {
+        _repository = repository;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="cancel"></param>
+    /// <returns></returns>
+    /// <exception cref="InvalidOperationException"></exception>
+    /// <exception cref="NotFoundException"></exception>
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    public async Task Handle(UpdateEmailTemplateCommand request, CancellationToken cancel)
+    {
+        EmailTemplateDto? temp;
+
+        if (request.EmailTemplateQuery?.Id is int id)
+        {
+            temp = await _repository.ReadOrDefaultAsync<EmailTemplateDto>(t => t.Id == id, single: false, cancel);
+        }
+        else if (request!.EmailTemplateQuery!.Type is Constants.EmailTemplateType type)
+        {
+            temp = await _repository.ReadOrDefaultAsync<EmailTemplateDto>(t => t.Name == type.ToString(), single: false, cancel);
+        }
+        else
+        {
+            throw new InvalidOperationException("Both id and type is null. Id: " + request.EmailTemplateQuery.Id +". Type: " + request.EmailTemplateQuery.Type.ToString());
+        }
+
+        if (temp == null)
+        {
+            throw new NotFoundException();
+        }
+
+        if (request.Body is not null)
+            temp.Body = request.Body;
+
+        if (request.Subject is not null)
+            temp.Subject = request.Subject;
+
+        await _repository.UpdateAsync(temp, t => t.Id == temp.Id, cancel);
+    }
+}

EnvelopeGenerator.Application/EmailTemplates/EmailTemplateQuery.cs

@@ -0,0 +1,24 @@
+using EnvelopeGenerator.Domain;
+
+namespace EnvelopeGenerator.Application.EmailTemplates;
+
+/// <summary>
+/// Repräsentiert eine Abfrage für E-Mail-Vorlagen, die für Absender und Empfänger von Umschlägen verwendet werden.
+/// Die Standardkultur ist "de-DE".
+/// </summary>
+/// <param name="Id">Die eindeutige Kennung der E-Mail-Vorlage (optional).</param>
+/// <param name="Type">Der Typ der E-Mail-Vorlage, z. B. <see cref="Constants.EmailTemplateType"/> (optional). Beispiele:
+/// 0 - DocumentReceived: Benachrichtigung über den Empfang eines Dokuments.
+/// 1 - DocumentSigned: Benachrichtigung über die Unterzeichnung eines Dokuments.
+/// 2 - DocumentDeleted: Benachrichtigung über das Löschen eines Dokuments.
+/// 3 - DocumentCompleted: Benachrichtigung über den Abschluss eines Dokuments.
+/// 4 - DocumentAccessCodeReceived: Benachrichtigung über den Erhalt eines Zugangscodes.
+/// 5 - DocumentShared: Benachrichtigung über das Teilen eines Dokuments.
+/// 6 - TotpSecret: Benachrichtigung über ein TOTP-Geheimnis.
+/// 7 - DocumentRejected_ADM (Für den Absender): Mail an den Absender, wenn das Dokument abgelehnt wird.
+/// 8 - DocumentRejected_REC (Für den ablehnenden Empfänger): Mail an den ablehnenden Empfänger, wenn das Dokument abgelehnt wird.
+/// 9 - DocumentRejected_REC_2 (Für sonstige Empfänger): Mail an andere Empfänger (Brief), wenn das Dokument abgelehnt wird.
+/// </param>
+public record EmailTemplateQuery(int? Id = null, Constants.EmailTemplateType? Type = null)
+{
+}

EnvelopeGenerator.Application/EmailTemplates/Queries/Read/ReadEmailTemplateMappingProfile.cs

@@ -0,0 +1,23 @@
+using AutoMapper;
+using EnvelopeGenerator.Domain.Entities;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Queries.Read;
+
+/// <summary>
+/// 
+/// </summary>
+public class ReadEmailTemplateMappingProfile : Profile
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public ReadEmailTemplateMappingProfile()
+    {
+        CreateMap<EmailTemplate, ReadEmailTemplateResponse>();
+    }
+}

EnvelopeGenerator.Application/EmailTemplates/Queries/Read/ReadEmailTemplateQuery.cs

@@ -0,0 +1,12 @@
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Queries.Read;
+
+
+/// <summary>
+/// Stellt eine Abfrage dar, um eine E-Mail-Vorlage zu lesen.
+/// Diese Klasse erbt von <see cref="EmailTemplateQuery"/>.
+/// </summary>
+public record ReadEmailTemplateQuery : EmailTemplateQuery, IRequest<ReadEmailTemplateResponse?>
+{
+}

EnvelopeGenerator.Application/EmailTemplates/Queries/Read/ReadEmailTemplateQueryHandler.cs

@@ -0,0 +1,52 @@
+using AutoMapper;
+using EnvelopeGenerator.Application.Contracts.Repositories;
+using EnvelopeGenerator.Domain;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Queries.Read;
+
+/// <summary>
+/// 
+/// </summary>
+public class ReadEmailTemplateQueryHandler : IRequestHandler<ReadEmailTemplateQuery, ReadEmailTemplateResponse?>
+{
+    private readonly IMapper _mapper;
+
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    private readonly IEmailTemplateRepository _repository;
+
+    /// <summary>
+    /// Initialisiert eine neue Instanz der <see cref="EmailTemplateController"/>-Klasse.
+    /// </summary>
+    /// <param name="mapper">
+    /// <param name="repository">
+    /// Die AutoMapper-Instanz, die zum Zuordnen von Objekten verwendet wird.
+    /// </param>
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    public ReadEmailTemplateQueryHandler(IMapper mapper, IEmailTemplateRepository repository)
+    {
+        _mapper = mapper;
+        _repository = repository;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    /// <exception cref="InvalidOperationException"></exception>
+    [Obsolete("Use IRepository")]
+    public async Task<ReadEmailTemplateResponse?> Handle(ReadEmailTemplateQuery request, CancellationToken cancellationToken)
+    {
+        var temp = request.Id is int id
+            ? await _repository.ReadByIdAsync(id)
+            : request.Type is Constants.EmailTemplateType type
+                ? await _repository.ReadByNameAsync(type)
+                : throw new InvalidOperationException("Either a valid integer ID or a valid EmailTemplateType must be provided in the request.");
+
+        var res = _mapper.Map<ReadEmailTemplateResponse>(temp);
+
+        return res;
+    }
+}

EnvelopeGenerator.Application/EmailTemplates/Queries/Read/ReadEmailTemplateResponse.cs

@@ -0,0 +1,37 @@
+namespace EnvelopeGenerator.Application.EmailTemplates.Queries.Read;
+
+/// <summary>
+/// Stellt die Antwort für eine Abfrage von E-Mail-Vorlagen bereit.
+/// </summary>
+public class ReadEmailTemplateResponse
+{
+    /// <summary>
+    /// Die eindeutige Kennung der E-Mail-Vorlage.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Name des Typs
+    /// </summary>
+    public required string Name { get; set; }
+
+    /// <summary>
+    /// Das Datum und die Uhrzeit, wann die Vorlage hinzugefügt wurde.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Der Inhalt (Body) der E-Mail-Vorlage. Kann null sein.
+    /// </summary>
+    public string? Body { get; set; }
+
+    /// <summary>
+    /// Der Betreff der E-Mail-Vorlage. Kann null sein.
+    /// </summary>
+    public string? Subject { get; set; }
+
+    /// <summary>
+    /// Das Datum und die Uhrzeit, wann die Vorlage zuletzt geändert wurde. Kann null sein.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+}

EnvelopeGenerator.Application/EnvelopeFlag.cs

@@ -0,0 +1,10 @@
+namespace EnvelopeGenerator.Application
+{
+    public enum EnvelopeFlag
+    {
+        EnvelopeOrReceiverNonexists,
+        NonDecodableEnvelopeReceiverId,
+        WrongEnvelopeReceiverId,
+        AccessCodeNull
+    }
+}

EnvelopeGenerator.Application/EnvelopeGenerator.Application.csproj

@@ -0,0 +1,86 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+	<PropertyGroup>
+		<TargetFrameworks>net7.0;net8.0;net9.0</TargetFrameworks>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<Nullable>enable</Nullable>
+		<GenerateDocumentationFile>true</GenerateDocumentationFile>
+		<DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
+	</PropertyGroup>
+
+	<ItemGroup>
+		<None Remove="Resources\Model.Designer.vb" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<PackageReference Include="Dapper" Version="2.1.66" />
+		<PackageReference Include="DigitalData.Core.Abstraction.Application" Version="1.0.0" />
+		<PackageReference Include="DigitalData.Core.Application" Version="3.3.4" />
+		<PackageReference Include="DigitalData.Core.Client" Version="2.1.0" />
+		<PackageReference Include="DigitalData.EmailProfilerDispatcher" Version="3.1.1" />
+		<PackageReference Include="MediatR" Version="12.5.0" />
+		<PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="7.0.18" />
+		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.5" />
+		<PackageReference Include="Otp.NET" Version="1.4.0" />
+		<PackageReference Include="QRCoder" Version="1.6.0" />
+		<PackageReference Include="QRCoder-ImageSharp" Version="0.10.0" />
+		<PackageReference Include="UserManager" Version="1.1.1" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<ProjectReference Include="..\EnvelopeGenerator.Domain\EnvelopeGenerator.Domain.csproj" />
+		<ProjectReference Include="..\EnvelopeGenerator.Extensions\EnvelopeGenerator.Extensions.csproj" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<Compile Update="Resources\Model.Designer.cs">
+			<DesignTime>True</DesignTime>
+			<AutoGen>True</AutoGen>
+			<DependentUpon>Model.resx</DependentUpon>
+		</Compile>
+	</ItemGroup>
+
+	<ItemGroup>
+		<EmbeddedResource Update="Resources\Model.en.resx">
+			<CustomToolNamespace>My.Resources</CustomToolNamespace>
+			<LastGenOutput>Model.en.Designer.vb</LastGenOutput>
+			<Generator>PublicResXFileCodeGenerator</Generator>
+		</EmbeddedResource>
+		<EmbeddedResource Update="Resources\Model.resx">
+			<CustomToolNamespace>My.Resources</CustomToolNamespace>
+			<LastGenOutput>Model.Designer.cs</LastGenOutput>
+			<Generator>PublicResXFileCodeGenerator</Generator>
+		</EmbeddedResource>
+		<EmbeddedResource Update="Resources\Resource.de-DE.resx">
+			<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+		</EmbeddedResource>
+		<EmbeddedResource Update="Resources\Resource.en-US.resx">
+			<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+		</EmbeddedResource>
+	</ItemGroup>
+
+	<ItemGroup Condition="'$(TargetFramework)' == 'net7.0'">
+	  <PackageReference Include="AutoMapper" Version="13.0.1" />
+	  <PackageReference Include="Microsoft.Data.SqlClient" Version="5.2.3" />
+	  <PackageReference Include="CommandDotNet">
+		<Version>7.0.5</Version>
+	  </PackageReference>
+	</ItemGroup>
+
+	<ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
+	  <PackageReference Include="AutoMapper" Version="14.0.0" />
+	  <PackageReference Include="Microsoft.Data.SqlClient" Version="6.0.2" />
+	  <PackageReference Include="CommandDotNet">
+	    <Version>8.1.1</Version>
+	  </PackageReference>
+	</ItemGroup>
+
+	<ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
+	  <PackageReference Include="AutoMapper" Version="14.0.0" />
+	  <PackageReference Include="Microsoft.Data.SqlClient" Version="6.0.2" />
+	  <PackageReference Include="CommandDotNet">
+	    <Version>8.1.1</Version>
+	  </PackageReference>
+	</ItemGroup>
+
+</Project>

EnvelopeGenerator.Application/EnvelopeReceivers/Commands/Create/CreateEnvelopeReceiverCommand.cs

@@ -0,0 +1,21 @@
+using EnvelopeGenerator.Application.Envelopes.Commands;
+using MediatR;
+using System.ComponentModel.DataAnnotations;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+
+/// <summary>
+/// Befehl zur Erstellung eines Umschlags.
+/// </summary>
+/// <param name="Title">Der Titel des Umschlags. Dies ist ein Pflichtfeld.</param>
+/// <param name="Message">Die Nachricht, die im Umschlag enthalten sein soll. Dies ist ein Pflichtfeld.</param>
+/// <param name="Document">Das mit dem Umschlag verknüpfte Dokument. Dies ist ein Pflichtfeld.</param>
+/// <param name="Receivers">Eine Sammlung von Empfängern, die den Umschlag erhalten. Dies ist ein Pflichtfeld.</param>
+/// <param name="TFAEnabled">Gibt an, ob die Zwei-Faktor-Authentifizierung für den Umschlag aktiviert ist. Standardmäßig false.</param>
+public record CreateEnvelopeReceiverCommand(
+    [Required] string Title,
+    [Required] string Message,
+    [Required] DocumentCreateCommand Document,
+    [Required] IEnumerable<ReceiverGetOrCreateCommand> Receivers,
+    bool TFAEnabled = false
+    ) : CreateEnvelopeCommand(Title, Message, TFAEnabled), IRequest<CreateEnvelopeReceiverResponse>;

EnvelopeGenerator.Application/EnvelopeReceivers/Commands/Create/CreateEnvelopeReceiverCommandHandler.cs

@@ -0,0 +1,67 @@
+using AutoMapper;
+using EnvelopeGenerator.Application.Contracts.SQLExecutor;
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+
+/// <summary>
+/// Handles the creation of an envelope along with its associated document and recipients.
+/// This command processes the envelope data, including title, message, document content,
+/// recipient list, and optional two-factor authentication settings.
+/// </summary>
+public class CreateEnvelopeReceiverCommandHandler : IRequestHandler<CreateEnvelopeReceiverCommand, CreateEnvelopeReceiverResponse>
+{
+    private readonly IMapper _mapper;
+
+    private readonly IEnvelopeExecutor _envelopeExecutor;
+
+    private readonly IEnvelopeReceiverExecutor _erExecutor;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="mapper"></param>
+    /// <param name="envelopeExecutor"></param>
+    /// <param name="erExecutor"></param>
+    public CreateEnvelopeReceiverCommandHandler(IMapper mapper, IEnvelopeExecutor envelopeExecutor, IEnvelopeReceiverExecutor erExecutor)
+    {
+        _mapper = mapper;
+        _envelopeExecutor = envelopeExecutor;
+        _erExecutor = erExecutor;
+    }
+
+    /// <summary>
+    /// Handles the execution of the <see cref="CreateEnvelopeReceiverCommand"/>.
+    /// Responsible for validating input data, creating or retrieving recipients, associating signatures,
+    /// and storing the envelope and document details.
+    /// </summary>
+    /// <param name="request">The command containing all necessary information to create an envelope.</param>
+    /// <param name="cancel">Token to observe while waiting for the task to complete.</param>
+    /// <returns>A task representing the asynchronous operation.</returns>
+    public async Task<CreateEnvelopeReceiverResponse> Handle(CreateEnvelopeReceiverCommand request, CancellationToken cancel)
+    {
+        int userId = request.UserId ?? throw new InvalidOperationException("UserId cannot be null when creating an envelope.");
+
+        var envelope = await _envelopeExecutor.CreateEnvelopeAsync(userId, request.Title, request.Message, request.TFAEnabled, cancel);
+
+        List<EnvelopeReceiver> sentRecipients = new();
+        List<ReceiverGetOrCreateCommand> unsentRecipients = new();
+
+        foreach (var receiver in request.Receivers)
+        {
+            var envelopeReceiver = await _erExecutor.AddEnvelopeReceiverAsync(envelope.Uuid, receiver.EmailAddress, receiver.Salution, receiver.PhoneNumber, cancel);
+
+            if (envelopeReceiver is null)
+                unsentRecipients.Add(receiver);
+            else
+                sentRecipients.Add(envelopeReceiver);
+        }
+
+        var res = _mapper.Map<CreateEnvelopeReceiverResponse>(envelope);
+        res.UnsentReceivers = unsentRecipients;
+        res.SentReceiver = _mapper.Map<IEnumerable<ReceiverReadDto>>(sentRecipients);
+        return res;
+    }
+}

EnvelopeGenerator.Application/EnvelopeReceivers/Commands/Create/CreateEnvelopeReceiverDtos.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+
+#region DTOs
+/// <summary>
+/// Signaturposition auf einem Dokument.
+/// </summary>
+/// <param name="X">X-Position</param>
+/// <param name="Y">Y-Position</param>
+/// <param name="Page">Seite, auf der sie sich befindet</param>
+public record Signature([Required] double X, [Required] double Y, [Required] int Page);
+
+/// <summary>
+/// DTO für Empfänger, die erstellt oder abgerufen werden sollen.
+/// Wenn nicht, wird sie erstellt und mit einer Signatur versehen.
+/// </summary>
+/// <param name="Signatures">Unterschriften auf Dokumenten.</param>
+/// <param name="Salution">Der Name, mit dem der Empfänger angesprochen werden soll. Bei Null oder keinem Wert wird der zuletzt verwendete Name verwendet.</param>
+/// <param name="PhoneNumber">Sollte mit Vorwahl geschrieben werden</param>
+public record ReceiverGetOrCreateCommand([Required] IEnumerable<Signature> Signatures, string? Salution = null, string? PhoneNumber = null)
+{
+    private string _emailAddress = string.Empty;
+
+    /// <summary>
+    /// E-Mail-Adresse des Empfängers.
+    /// </summary>
+    [Required]
+    public string EmailAddress { get => _emailAddress.ToLower(); init => _emailAddress = value.ToLower(); }
+};
+
+/// <summary>
+/// DTO zum Erstellen eines Dokuments.
+/// </summary>
+public record DocumentCreateCommand()
+{
+    /// <summary>
+    /// Die Dokumentdaten im Base64-String-Format. Wird verwendet, wenn das Dokument als Base64-codierter String bereitgestellt wird.
+    /// </summary>
+    [Required]
+    public required string DataAsBase64 { get; init; }
+};
+#endregion

EnvelopeGenerator.Application/EnvelopeReceivers/Commands/Create/CreateEnvelopeReceiverMappingProfile.cs

@@ -0,0 +1,21 @@
+using AutoMapper;
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using EnvelopeGenerator.Application.Envelopes.Commands;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+
+/// <summary>
+/// 
+/// </summary>
+public class CreateEnvelopeReceiverMappingProfile : Profile
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public CreateEnvelopeReceiverMappingProfile()
+    {
+        CreateMap<Envelope, CreateEnvelopeResponse>();
+        CreateMap<Receiver, ReceiverReadDto>();
+    }
+}

EnvelopeGenerator.Application/EnvelopeReceivers/Commands/Create/CreateEnvelopeReceiverResponse.cs

@@ -0,0 +1,39 @@
+using DigitalData.UserManager.Domain.Entities;
+using EnvelopeGenerator.Application.DTOs.Receiver;
+using EnvelopeGenerator.Application.Envelopes.Commands;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+
+/// <summary>
+/// 
+/// </summary>
+public record CreateEnvelopeReceiverResponse : CreateEnvelopeResponse
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="Id"></param>
+    /// <param name="UserId"></param>
+    /// <param name="Status"></param>
+    /// <param name="Uuid"></param>
+    /// <param name="Message"></param>
+    /// <param name="AddedWhen"></param>
+    /// <param name="ChangedWhen"></param>
+    /// <param name="Title"></param>
+    /// <param name="Language"></param>
+    /// <param name="TFAEnabled"></param>
+    /// <param name="User"></param>
+    public CreateEnvelopeReceiverResponse(int Id, int UserId, int Status, string Uuid, string? Message, DateTime AddedWhen, DateTime? ChangedWhen, string? Title, string Language, bool TFAEnabled, User User) : base(Id, UserId, Status, Uuid, Message, AddedWhen, ChangedWhen, Title, Language, TFAEnabled, User)
+    {
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public IEnumerable<ReceiverReadDto> SentReceiver { get; set; } = new List<ReceiverReadDto>();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public IEnumerable<ReceiverGetOrCreateCommand> UnsentReceivers { get; set; } = new List<ReceiverGetOrCreateCommand>();
+}

EnvelopeGenerator.Application/EnvelopeReceivers/EnvelopeReceiverQuery.cs

@@ -0,0 +1,47 @@
+using EnvelopeGenerator.Application.Histories;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers;
+
+/// <summary>
+/// Stellt eine Abfrage für einen Envelope-Empfänger dar.
+/// </summary>
+/// <param name="Status">Der Status der Abfrage, optional.</param>
+public record EnvelopeReceiverQuery(EnvelopeStatusQuery? Status = null);
+
+/// <summary>
+/// Repräsentiert den Status eines Umschlags und dessen Beziehung zum Empfänger. (vgl. auch <see cref="Common.Constants.EnvelopeStatus"/>
+/// Invalid (0): Ungültiger Status.
+/// EnvelopeCreated (1001): Der Umschlag wurde erstellt.
+/// EnvelopeSaved (1002): Der Umschlag wurde gespeichert.
+/// EnvelopeQueued (1003): Der Umschlag wurde zur Verarbeitung eingeplant.
+/// EnvelopeSent (1004): Der Umschlag wurde versendet. (Nicht verwendet)
+/// EnvelopePartlySigned (1005): Der Umschlag wurde teilweise unterschrieben.
+/// EnvelopeCompletelySigned (1006): Der Umschlag wurde vollständig unterschrieben.
+/// EnvelopeReportCreated (1007): Ein Abschlussbericht wurde für den Umschlag erstellt.
+/// EnvelopeArchived (1008): Der Umschlag wurde archiviert.
+/// EnvelopeDeleted (1009): Der Umschlag wurde gelöscht.
+/// AccessCodeRequested (2001): Der Zugriffscode wurde angefordert.
+/// AccessCodeCorrect (2002): Der Zugriffscode war korrekt.
+/// AccessCodeIncorrect (2003): Der Zugriffscode war falsch.
+/// DocumentOpened (2004): Das Dokument wurde geöffnet.
+/// DocumentSigned (2005): Ein Dokument wurde unterschrieben.
+/// SignatureConfirmed (2006): Die Signatur wurde bestätigt.
+/// DocumentRejected (2007): Ein Dokument wurde abgelehnt.
+/// EnvelopeShared (2008): Der Umschlag wurde geteilt.
+/// EnvelopeViewed (2009): Der Umschlag wurde angesehen.
+/// DocumentForwarded (4001): Das Dokument wurde weitergeleitet.
+/// MessageInvitationSent (3001): Einladung wurde gesendet (vom Trigger verwendet).
+/// MessageAccessCodeSent (3002): Zugriffscode wurde gesendet.
+/// MessageConfirmationSent (3003): Bestätigungsnachricht wurde gesendet.
+/// MessageDeletionSent (3004): Löschbenachrichtigung wurde gesendet.
+/// MessageCompletionSent (3005): Abschlussbenachrichtigung wurde gesendet.
+/// <param name="Min">Der minimale Statuswert, der berücksichtigt werden soll.</param>
+/// <param name="Max">Der maximale Statuswert, der berücksichtigt werden soll.</param>
+/// <param name="Ignore">Eine Liste von Statuswerten, die ignoriert werden sollen.</param>
+/// </summary>
+public record EnvelopeStatusQuery(
+    int? Min = null,
+    int? Max = null,
+    int[]? Ignore = null)
+{
+}

EnvelopeGenerator.Application/EnvelopeReceivers/Queries/Read/ReadEnvelopeReceiverQuery.cs

@@ -0,0 +1,30 @@
+using EnvelopeGenerator.Application.Histories;
+using EnvelopeGenerator.Application.Envelopes.Queries.Read;
+using EnvelopeGenerator.Application.Receivers.Queries.Read;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Queries.Read;
+
+/// <summary>
+/// Repräsentiert eine Abfrage zum Lesen eines Envelope-Empfängers.
+/// </summary>
+/// <remarks>
+/// Diese Abfrage kombiniert Informationen über einen Umschlag (<see cref="ReadEnvelopeQuery"/>) 
+/// und einen Empfänger (<see cref="ReadReceiverQuery"/>), um eine vollständige Antwort 
+/// (<see cref="ReadEnvelopeReceiverResponse"/>) zu generieren. 
+/// Die Antwort enthält Details wie den Status, die Zuordnung zwischen Umschlag und Empfänger 
+/// sowie zusätzliche Metadaten.
+/// </remarks>
+/// <param name="Status">Umschlag oder Empfängerstatus.</param>
+public record ReadEnvelopeReceiverQuery(EnvelopeStatusQuery? Status = null) : EnvelopeReceiverQuery(Status), IRequest<ReadEnvelopeReceiverResponse>
+{
+    /// <summary>
+    /// Der Umschlag, der mit dem Empfänger verknüpft ist.
+    /// </summary>
+    public ReadEnvelopeQuery? Envelope { get; init; }
+
+    /// <summary>
+    /// Der Empfänger, der mit dem Umschlag verknüpft ist.
+    /// </summary>
+    public ReadReceiverQuery? Receiver { get; init; }
+};

EnvelopeGenerator.Application/EnvelopeReceivers/Queries/Read/ReadEnvelopeReceiverResponse.cs

@@ -0,0 +1,94 @@
+using DigitalData.EmailProfilerDispatcher.Abstraction.Attributes;
+using EnvelopeGenerator.Application.Envelopes.Queries.Read;
+using EnvelopeGenerator.Application.Receivers.Queries.Read;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Queries.Read;
+
+/// <summary>
+/// Repräsentiert die Antwort für das Lesen eines Envelope-Empfängers.
+/// </summary>
+/// <remarks>
+/// Diese Klasse enthält Informationen über einen spezifischen Empfänger eines Umschlags (Envelope).
+/// Sie verknüpft die Empfängerinformationen mit den zugehörigen Umschlagsdaten und bietet zusätzliche Metadaten.
+/// </remarks>
+/// <param name="UserId">Die eindeutige Kennung des Benutzers, der den Empfänger erstellt hat.</param>
+/// <param name="Status">Der Status des Empfängers als numerischer Wert.</param>
+public record ReadEnvelopeReceiverResponse(int UserId, int Status)
+{
+    /// <summary>
+    /// Gibt die zusammengesetzte Kennung des Empfängers zurück, bestehend aus der Umschlags-ID und der Empfänger-ID.
+    /// </summary>
+    /// <remarks>
+    /// Diese Eigenschaft kombiniert die eindeutige Kennung des Umschlags (EnvelopeId) und die des Empfängers (ReceiverId) 
+    /// zu einer einzigen, leicht zugänglichen Struktur.
+    /// </remarks>
+    [NotMapped]
+    public (int Envelope, int Receiver) Id => (Envelope: EnvelopeId, Receiver: ReceiverId);
+
+    /// <summary>
+    /// Die eindeutige Kennung des zugehörigen Umschlags.
+    /// </summary>
+    [Required]
+    public int EnvelopeId { get; init; }
+
+    /// <summary>
+    /// Die eindeutige Kennung des Empfängers.
+    /// </summary>
+    [Required]
+    public int ReceiverId { get; init; }
+
+    /// <summary>
+    /// Die Reihenfolge des Empfängers innerhalb des Umschlags.
+    /// </summary>
+    public int Sequence { get; init; }
+
+    /// <summary>
+    /// Der Name des Empfängers. Kann als Platzhalter verwendet werden.
+    /// </summary>
+    [TemplatePlaceholder("[NAME_RECEIVER]")]
+    public string? Name { get; init; }
+
+    /// <summary>
+    /// Die Berufsbezeichnung des Empfängers.
+    /// </summary>
+    public string? JobTitle { get; init; }
+
+    /// <summary>
+    /// Der Firmenname des Empfängers.
+    /// </summary>
+    public string? CompanyName { get; init; }
+
+    /// <summary>
+    /// Eine private Nachricht, die mit dem Empfänger verknüpft ist.
+    /// </summary>
+    public string? PrivateMessage { get; init; }
+
+    /// <summary>
+    /// Das Datum und die Uhrzeit, wann der Empfänger hinzugefügt wurde.
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+
+    /// <summary>
+    /// Das Datum und die Uhrzeit, wann der Empfänger zuletzt geändert wurde (falls vorhanden).
+    /// </summary>
+    public DateTime? ChangedWhen { get; init; }
+
+    /// <summary>
+    /// Gibt an, ob der Empfänger eine Telefonnummer hat.
+    /// </summary>
+    public bool HasPhoneNumber { get; init; }
+
+    /// <summary>
+    /// Die zugehörigen Umschlagsdaten.
+    /// </summary>
+    [Required]
+    public required ReadEnvelopeResponse Envelope { get; init; }
+
+    /// <summary>
+    /// Die Liste der Empfängerinformationen.
+    /// </summary>
+    [Required]
+    public IEnumerable<ReadReceiverResponse> Receiver { get; init; } = new List<ReadReceiverResponse>();
+}

EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommand.cs

@@ -0,0 +1,26 @@
+using MediatR;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.Application.Envelopes.Commands;
+
+/// <summary>
+/// Befehl zur Erstellung eines Umschlags.
+/// </summary>
+/// <param name="Title">Der Titel des Umschlags. Dies ist ein Pflichtfeld.</param>
+/// <param name="Message">Die Nachricht, die im Umschlag enthalten sein soll. Dies ist ein Pflichtfeld.</param>
+/// <param name="TFAEnabled">Gibt an, ob die Zwei-Faktor-Authentifizierung für den Umschlag aktiviert ist. Standardmäßig false.</param>
+public record CreateEnvelopeCommand(
+    [Required] string Title,
+    [Required] string Message,
+    bool TFAEnabled = false
+    ) : IRequest<CreateEnvelopeResponse?>
+{
+    /// <summary>
+    /// Id of receiver
+    /// </summary>
+    [JsonIgnore]
+    [BindNever]
+    public int? UserId { get; set; }
+};

EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommandHandler.cs

@@ -0,0 +1,41 @@
+using AutoMapper;
+using EnvelopeGenerator.Application.Contracts.SQLExecutor;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.Envelopes.Commands;
+
+/// <summary>
+/// 
+/// </summary>
+public class CreateEnvelopeCommandHandler : IRequestHandler<CreateEnvelopeCommand, CreateEnvelopeResponse?>
+{
+    private readonly IEnvelopeExecutor _envelopeExecutor;
+
+    private readonly IMapper _mapper;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeExecutor"></param>
+    /// <param name="mapper"></param>
+    public CreateEnvelopeCommandHandler(IEnvelopeExecutor envelopeExecutor, IMapper mapper)
+    {
+        _envelopeExecutor = envelopeExecutor;
+        _mapper = mapper;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public async Task<CreateEnvelopeResponse?> Handle(CreateEnvelopeCommand request, CancellationToken cancellationToken)
+    {
+        int userId = request.UserId ?? throw new InvalidOperationException("UserId cannot be null when creating an envelope.");
+
+        var envelope = await _envelopeExecutor.CreateEnvelopeAsync(userId, request.Title, request.Message, request.TFAEnabled, cancellationToken);
+
+        return _mapper.Map<CreateEnvelopeResponse>(envelope);
+    }
+}

EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeMappingProfile.cs

@@ -0,0 +1,19 @@
+using AutoMapper;
+using EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Envelopes.Commands;
+
+/// <summary>
+/// 
+/// </summary>
+public class CreateEnvelopeMappingProfile : Profile
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public CreateEnvelopeMappingProfile()
+    {
+        CreateMap<Envelope, CreateEnvelopeReceiverResponse>();
+    }
+}

EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeResponse.cs

@@ -0,0 +1,20 @@
+using EnvelopeGenerator.Application.Envelopes.Queries.Read;
+
+namespace EnvelopeGenerator.Application.Envelopes.Commands;
+
+/// <summary>
+/// 
+/// </summary>
+/// <param name="Id"><inheritdoc/></param>
+/// <param name="UserId"><inheritdoc/></param>
+/// <param name="Status"><inheritdoc/></param>
+/// <param name="Uuid"><inheritdoc/></param>
+/// <param name="Message"><inheritdoc/></param>
+/// <param name="AddedWhen"><inheritdoc/></param>
+/// <param name="ChangedWhen"><inheritdoc/></param>
+/// <param name="Title"><inheritdoc/></param>
+/// <param name="Language"><inheritdoc/></param>
+/// <param name="TFAEnabled"><inheritdoc/></param>
+/// <param name="User"><inheritdoc/></param>
+public record CreateEnvelopeResponse(int Id, int UserId, int Status, string Uuid, string? Message, DateTime AddedWhen, DateTime? ChangedWhen, string? Title, string Language, bool TFAEnabled, DigitalData.UserManager.Domain.Entities.User User) 
+    : ReadEnvelopeResponse(Id, UserId, Status, Uuid, Message, AddedWhen, ChangedWhen, Title, Language, TFAEnabled, User);

EnvelopeGenerator.Application/Envelopes/EnvelopeQuery.cs

@@ -0,0 +1,16 @@
+using MediatR;
+
+namespace EnvelopeGenerator.Application.Envelopes;
+
+/// <summary>
+/// Repräsentiert eine Abfrage für Umschläge.
+/// </summary>
+/// <param name="Id">Die eindeutige Kennung des Umschlags.</param>
+/// <param name="Status">Der Status des Umschlags.</param>
+/// <param name="Uuid">Die universell eindeutige Kennung des Umschlags.</param>
+public record EnvelopeQuery(
+    int? Id = null,
+    int? Status = null,
+    string? Uuid = null) : IRequest
+{
+};

EnvelopeGenerator.Application/Envelopes/Queries/Read/ReadEnvelopeQuery.cs

@@ -0,0 +1,8 @@
+namespace EnvelopeGenerator.Application.Envelopes.Queries.Read;
+
+/// <summary>
+/// Stellt eine Abfrage zum Lesen von Briefumschlägen dar.
+/// </summary>
+public record ReadEnvelopeQuery : EnvelopeQuery
+{
+}

EnvelopeGenerator.Application/Envelopes/Queries/Read/ReadEnvelopeResponse.cs

@@ -0,0 +1,36 @@
+using EnvelopeGenerator.Domain;
+
+namespace EnvelopeGenerator.Application.Envelopes.Queries.Read;
+
+/// <summary>
+/// Repräsentiert die Antwort für das Lesen eines Umschlags.
+/// </summary>
+/// <param name="Id">Die eindeutige Kennung des Umschlags.</param>
+/// <param name="UserId">Die Kennung des Benutzers, der den Umschlag erstellt hat.</param>
+/// <param name="Status">Der Status des Umschlags als numerischer Wert.</param>
+/// <param name="Uuid">Die universelle eindeutige Kennung (UUID) des Umschlags.</param>
+/// <param name="Message">Eine optionale Nachricht, die mit dem Umschlag verknüpft ist.</param>
+/// <param name="AddedWhen">Das Datum und die Uhrzeit, wann der Umschlag hinzugefügt wurde.</param>
+/// <param name="ChangedWhen">Das Datum und die Uhrzeit, wann der Umschlag zuletzt geändert wurde (falls vorhanden).</param>
+/// <param name="Title">Ein optionaler Titel des Umschlags.</param>
+/// <param name="Language">Die Sprache, die mit dem Umschlag verknüpft ist.</param>
+/// <param name="TFAEnabled">Gibt an, ob die Zwei-Faktor-Authentifizierung (TFA) aktiviert ist.</param>
+/// <param name="User">Das Benutzerobjekt, das mit dem Umschlag verknüpft ist.</param>
+public record ReadEnvelopeResponse(
+    int Id,
+    int UserId,
+    int Status,
+    string Uuid,
+    string? Message,
+    DateTime AddedWhen,
+    DateTime? ChangedWhen,
+    string? Title,
+    string Language,
+    bool TFAEnabled,
+    DigitalData.UserManager.Domain.Entities.User User)
+{
+    /// <summary>
+    /// Gibt den Namen des Status zurück, der dem numerischen Statuswert entspricht.
+    /// </summary>
+    public string StatusName => ((Constants.EnvelopeStatus)Status).ToString();
+}

EnvelopeGenerator.Application/Envelopes/Queries/ReceiverName/ReadReceiverNameQuery.cs

@@ -0,0 +1,11 @@
+using EnvelopeGenerator.Application.Receivers.Queries.Read;
+
+namespace EnvelopeGenerator.Application.Envelopes.Queries.ReceiverName;
+
+/// <summary>
+/// Eine Abfrage, um die zuletzt verwendete Anrede eines Empfängers zu ermitteln, 
+/// damit diese für zukünftige Umschläge wiederverwendet werden kann.
+/// </summary>
+public record ReadReceiverNameQuery() : ReadReceiverQuery
+{
+}

EnvelopeGenerator.Application/Exceptions/BadRequestException.cs

@@ -0,0 +1,22 @@
+namespace EnvelopeGenerator.Application.Exceptions;
+
+/// <summary>
+/// Represents an exception that is thrown when a bad request is encountered.
+/// </summary>
+public class BadRequestException : Exception
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="BadRequestException"/> class.
+    /// </summary>
+    public BadRequestException()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="BadRequestException"/> class with a specified error message.
+    /// </summary>
+    /// <param name="message">The message that describes the error.</param>
+    public BadRequestException(string? message) : base(message)
+    {
+    }
+}

EnvelopeGenerator.Application/Exceptions/NotFoundException.cs

@@ -0,0 +1,22 @@
+namespace EnvelopeGenerator.Application.Exceptions;
+
+/// <summary>
+/// Represents an exception that is thrown when a requested resource is not found.
+/// </summary>
+public class NotFoundException : Exception
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="NotFoundException"/> class.
+    /// </summary>
+    public NotFoundException()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="NotFoundException"/> class with a specified error message.
+    /// </summary>
+    /// <param name="message">The message that describes the error.</param>
+    public NotFoundException(string? message) : base(message)
+    {
+    }
+}

EnvelopeGenerator.Application/Extensions/CacheExtensions.cs

@@ -0,0 +1,222 @@
+using Microsoft.Extensions.Caching.Distributed;
+
+namespace EnvelopeGenerator.Application.Extensions;
+
+/// <summary>
+/// 
+/// </summary>
+public static class CacheExtensions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="value"></param>
+    /// <param name="options"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static Task SetLongAsync(this IDistributedCache cache, string key, long value, DistributedCacheEntryOptions? options = null, CancellationToken cToken = default)
+        => options is null
+            ? cache.SetAsync(key, BitConverter.GetBytes(value), token: cToken)
+            : cache.SetAsync(key, BitConverter.GetBytes(value), options: options, token: cToken);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<long?> GetLongAsync(this IDistributedCache cache, string key, CancellationToken cToken = default)
+    {
+        var value = await cache.GetAsync(key, cToken);
+        return value is null ? null : BitConverter.ToInt64(value, 0);
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="value"></param>
+    /// <param name="options"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static Task SetDateTimeAsync(this IDistributedCache cache, string key, DateTime value, DistributedCacheEntryOptions? options = null, CancellationToken cToken = default)
+        => cache.SetLongAsync(key: key, value: value.Ticks, options: options, cToken: cToken);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<DateTime?> GetDateTimeAsync(this IDistributedCache cache, string key, CancellationToken cToken = default)
+    {
+        var value = await cache.GetAsync(key, cToken);
+        return value is null ? null : new(BitConverter.ToInt64(value, 0));
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="value"></param>
+    /// <param name="options"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static Task SetTimeSpanAsync(this IDistributedCache cache, string key, TimeSpan value, DistributedCacheEntryOptions? options = null, CancellationToken cToken = default)
+        => cache.SetLongAsync(key: key, value: value.Ticks, options: options, cToken);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<TimeSpan?> GetTimeSpanAsync(this IDistributedCache cache, string key, CancellationToken cToken = default)
+    {
+        var value = await cache.GetAsync(key, cToken);
+        return value is null ? null : new(BitConverter.ToInt64(value, 0));
+    }
+
+    //TODO: use code generator
+    #region GetOrSetAsync
+
+    #region string
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factory"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<string> GetOrSetAsync(this IDistributedCache cache, string key, Func<string> factory, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        var value = await cache.GetStringAsync(key, cToken);
+        if (value is null)
+        {
+            // create new and save
+            value = factory();
+
+            Task CacheAsync() => options is null
+                    ? cache.SetStringAsync(key, value, cToken)
+                    : cache.SetStringAsync(key, value, options, cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+        }
+
+        return value;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factoryAsync"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<string> GetOrSetAsync(this IDistributedCache cache, string key, Func<Task<string>> factoryAsync, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        var value = await cache.GetStringAsync(key, cToken);
+        if(value is null)
+        {
+            // create new and save
+            value = await factoryAsync();
+
+            Task CacheAsync() => options is null
+                ? cache.SetStringAsync(key: key, value: value, token: cToken)
+                : cache.SetStringAsync(key: key, value: value, options: options, token: cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+        }
+
+        return value;
+    }
+    #endregion
+
+    #region DateTime
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factory"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<DateTime> GetOrSetAsync(this IDistributedCache cache, string key, Func<DateTime> factory, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        if (await cache.GetDateTimeAsync(key, cToken) is DateTime dateTimeValue)
+            return dateTimeValue;
+        else
+        {
+            // create new and save
+            var newValue = factory();
+
+            Task CacheAsync() => options is null
+                    ? cache.SetDateTimeAsync(key, newValue, cToken: cToken)
+                    : cache.SetDateTimeAsync(key, newValue, options, cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+
+            return newValue;
+        }
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factory"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<DateTime> GetOrSetAsync(this IDistributedCache cache, string key, Func<Task<DateTime>> factory, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        if (await cache.GetDateTimeAsync(key, cToken) is DateTime dateTimeValue)
+            return dateTimeValue;
+        else
+        {
+            // create new and save
+            var newValue = await factory();
+
+            Task CacheAsync() => options is null
+                    ? cache.SetDateTimeAsync(key, newValue, cToken: cToken)
+                    : cache.SetDateTimeAsync(key, newValue, options, cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+
+            return newValue;
+        }
+    }
+    #endregion
+
+    #endregion
+}