diff --git a/src/Speckle.Sdk/Pipelines/Send/Uploader.cs b/src/Speckle.Sdk/Pipelines/Send/Uploader.cs
index 9d7103d9..1cd96f13 100644
--- a/src/Speckle.Sdk/Pipelines/Send/Uploader.cs
+++ b/src/Speckle.Sdk/Pipelines/Send/Uploader.cs
@@ -74,8 +74,8 @@ public sealed class Uploader : IDisposable
   {
     using DisposableFile tempFile = await WriteFile().ConfigureAwait(false);
 
-    PresignedUploadResponse presignedUpload = await GetPresignedUrl().ConfigureAwait(false);
-    await UploadToS3(tempFile.FileInfo, presignedUpload.Url).ConfigureAwait(false);
+    PresignedUploadResponse presignedUploadResponse = await GetPresignedUrl().ConfigureAwait(false);
+    await UploadToS3(tempFile.FileInfo, presignedUploadResponse).ConfigureAwait(false);
 
     return await TriggerProcessing().ConfigureAwait(false);
   }
@@ -123,7 +123,7 @@ public sealed class Uploader : IDisposable
     return presignedUpload;
   }
 
-  private async Task UploadToS3(FileInfo file, Uri s3Url)
+  private async Task UploadToS3(FileInfo file, PresignedUploadResponse presignedUploadResponse)
   {
     using var fileStreamUpload = new FileStream(file.FullName, FileMode.Open, FileAccess.Read, FileShare.Read);
 
@@ -133,7 +133,12 @@ public sealed class Uploader : IDisposable
     streamContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
     streamContent.Headers.ContentLength = file.Length;
 
-    using var uploadRequest = new HttpRequestMessage(HttpMethod.Put, s3Url);
+    using var uploadRequest = new HttpRequestMessage(HttpMethod.Put, presignedUploadResponse.Url);
+    foreach (var kvp in presignedUploadResponse.AdditionalRequestHeaders)
+    {
+      uploadRequest.Headers.Add(kvp.Key, kvp.Value);
+    }
+
     uploadRequest.Content = streamContent;
 
     using var uploadResponse = await _s3Client
diff --git a/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs b/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs
index fb020de4..cff5775b 100644
--- a/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs
+++ b/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs
@@ -9,6 +9,7 @@ internal record PresignedUploadResponse
 {
   public required Uri Url { get; init; }
   public required string Key { get; init; }
+  public Dictionary<string, string> AdditionalRequestHeaders { get; init; } = new();
 }
 
 internal record ProcessUploadResponse