diff --git a/EnvelopeGenerator.Application/Signatures/Behaviors/EnvelopeReceiverResolutionBehavior.cs b/EnvelopeGenerator.Application/Signatures/Behaviors/EnvelopeReceiverResolutionBehavior.cs
new file mode 100644
index 00000000..c90603e3
--- /dev/null
+++ b/EnvelopeGenerator.Application/Signatures/Behaviors/EnvelopeReceiverResolutionBehavior.cs
@@ -0,0 +1,54 @@
+using AutoMapper;
+using DigitalData.Core.Abstraction.Application.Repository;
+using DigitalData.Core.Exceptions;
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+using EnvelopeGenerator.Application.Common.Extensions;
+using EnvelopeGenerator.Application.Signatures.Commands;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+
+namespace EnvelopeGenerator.Application.Signatures.Behaviors;
+
+/// <summary>
+/// Pipeline behavior that resolves and validates EnvelopeReceiver.
+/// Executes FIRST in the signing process - before all other behaviors.
+/// If EnvelopeReceiver is not provided, it queries the database using EnvelopeReceiverQueryBase parameters.
+/// </summary>
+public class EnvelopeReceiverResolutionBehavior : IPipelineBehavior<SignCommand, Unit>
+{
+    private readonly IRepository<EnvelopeReceiver> _erRepo;
+    private readonly IMapper _mapper;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="erRepo"></param>
+    /// <param name="mapper"></param>
+    public EnvelopeReceiverResolutionBehavior(IRepository<EnvelopeReceiver> erRepo, IMapper mapper)
+    {
+        _erRepo = erRepo;
+        _mapper = mapper;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="next"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public async Task<Unit> Handle(SignCommand request, RequestHandlerDelegate<Unit> next, CancellationToken cancellationToken)
+    {
+        // If EnvelopeReceiver is not provided, query it from database
+        if (request.EnvelopeReceiver is null)
+        {
+            var er = await _erRepo.Query.Where(request, notnull: true).SingleOrDefaultAsync(cancellationToken)
+                ?? throw new NotFoundException("EnvelopeReceiver not found");
+
+            request.SetEnvelopeReceiver(_mapper.Map<EnvelopeReceiverDto>(er));
+        }
+
+        return await next(cancellationToken);
+    }
+}