diff --git a/EnvelopeGenerator.API/Controllers/EnvelopeReceiverController.cs b/EnvelopeGenerator.API/Controllers/EnvelopeReceiverController.cs
index e8125779..db8371ee 100644
--- a/EnvelopeGenerator.API/Controllers/EnvelopeReceiverController.cs
+++ b/EnvelopeGenerator.API/Controllers/EnvelopeReceiverController.cs
@@ -66,16 +66,7 @@ public class EnvelopeReceiverController : ControllerBase
     [HttpGet]
     public async Task<IActionResult> GetEnvelopeReceiver([FromQuery] ReadEnvelopeReceiverQuery envelopeReceiver)
     {
-        var username = User.GetUsernameOrDefault();
-
-        if (username is null)
-        {
-            _logger.LogError(@"Envelope Receiver dto cannot be sent because username claim is null. Potential authentication and authorization error. The value of other claims are [id: {id}], [username: {username}], [name: {name}], [prename: {prename}], [email: {email}].",
-                User.GetId(), User.GetUsernameOrDefault(), User.GetNameOrDefault(), User.GetPrenameOrDefault(), User.GetEmailOrDefault());
-            return StatusCode(StatusCodes.Status500InternalServerError);
-        }
-
-        envelopeReceiver = envelopeReceiver with { Username = username };
+        envelopeReceiver = envelopeReceiver with { Username = User.GetUsername() };
 
         var result = await _mediator.Send(envelopeReceiver);
 
diff --git a/EnvelopeGenerator.API/Extensions/SenderClaimExtensions.cs b/EnvelopeGenerator.API/Extensions/SenderClaimExtensions.cs
index 9284aca4..613d9157 100644
--- a/EnvelopeGenerator.API/Extensions/SenderClaimExtensions.cs
+++ b/EnvelopeGenerator.API/Extensions/SenderClaimExtensions.cs
@@ -24,15 +24,6 @@ namespace EnvelopeGenerator.API.Extensions
             throw new InvalidOperationException(message);
         }
 
-        /// <summary>
-        /// Attempts to retrieve the user's ID from the claims. Returns null if the ID is not found or invalid.
-        /// </summary>
-        /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
-        /// <returns>The user's ID as an integer, or null if not found or invalid.</returns>
-        public static int? GetIdOrDefault(this ClaimsPrincipal user)
-            => int.TryParse(user.FindFirstValue(ClaimTypes.NameIdentifier) ?? user.FindFirstValue("sub"), out int result)
-                ? result : null;
-
         /// <summary>
         /// Retrieves the user's ID from the claims. Throws an exception if the ID is missing or invalid.
         /// </summary>
@@ -40,39 +31,48 @@ namespace EnvelopeGenerator.API.Extensions
         /// <returns>The user's ID as an integer.</returns>
         /// <exception cref="InvalidOperationException">Thrown if the user ID claim is missing or invalid.</exception>
         public static int GetId(this ClaimsPrincipal user)
-            => user.GetIdOrDefault()
-            ?? throw new InvalidOperationException("User ID claim is missing or invalid. This may indicate a misconfigured or forged JWT token.");
+        {
+            var idValue = user.FindFirstValue(ClaimTypes.NameIdentifier) ?? user.FindFirstValue("sub");
+            idValue ??= user.GetRequiredClaimOfSender(ClaimTypes.NameIdentifier);
+
+            if (!int.TryParse(idValue, out var result))
+            {
+                throw new InvalidOperationException("User ID claim is missing or invalid. This may indicate a misconfigured or forged JWT token.");
+            }
+
+            return result;
+        }
 
         /// <summary>
-        /// Retrieves the username from the claims, if available.
+        /// Retrieves the username from the claims.
         /// </summary>
         /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
-        /// <returns>The username as a string, or null if not found.</returns>
-        public static string? GetUsernameOrDefault(this ClaimsPrincipal user)
-            => user.FindFirst(ClaimTypes.Name)?.Value;
+        /// <returns>The username as a string.</returns>
+        public static string GetUsername(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.Name);
 
         /// <summary>
-        /// Retrieves the user's surname (last name) from the claims, if available.
+        /// Retrieves the user's surname (last name) from the claims.
         /// </summary>
         /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
-        /// <returns>The surname as a string, or null if not found.</returns>
-        public static string? GetNameOrDefault(this ClaimsPrincipal user)
-            => user.FindFirst(ClaimTypes.Surname)?.Value;
+        /// <returns>The surname as a string.</returns>
+        public static string GetName(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.Surname);
 
         /// <summary>
-        /// Retrieves the user's given name (first name) from the claims, if available.
+        /// Retrieves the user's given name (first name) from the claims.
         /// </summary>
         /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
-        /// <returns>The given name as a string, or null if not found.</returns>
-        public static string? GetPrenameOrDefault(this ClaimsPrincipal user)
-            => user.FindFirst(ClaimTypes.GivenName)?.Value;
+        /// <returns>The given name as a string.</returns>
+        public static string GetPrename(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.GivenName);
 
         /// <summary>
-        /// Retrieves the user's email address from the claims, if available.
+        /// Retrieves the user's email address from the claims.
         /// </summary>
         /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
-        /// <returns>The email address as a string, or null if not found.</returns>
-        public static string? GetEmailOrDefault(this ClaimsPrincipal user)
-            => user.FindFirst(ClaimTypes.Email)?.Value;
+        /// <returns>The email address as a string.</returns>
+        public static string GetEmail(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.Email);
     }
 }
\ No newline at end of file