diff --git a/src/Speckle.Sdk/Api/Blob/BlobApi.cs b/src/Speckle.Sdk/Api/Blob/BlobApi.cs
index 1dd68eb5..10939f6d 100644
--- a/src/Speckle.Sdk/Api/Blob/BlobApi.cs
+++ b/src/Speckle.Sdk/Api/Blob/BlobApi.cs
@@ -193,30 +193,7 @@ public sealed class BlobApi : IBlobApi
     using var response = await _unauthedClient.SendAsync(requestMessage, cancellationToken).ConfigureAwait(false);
     response.EnsureSuccessStatusCode();
 
-    return ParseEtagHeader(response.Headers);
-  }
-
-  private static string ParseEtagHeader(HttpResponseHeaders headers)
-  {
-    if (!headers.TryGetValues("ETag", out var etagValues))
-    {
-      throw new ArgumentException(
-        "Response does not have an ETag attached to it, cannot use this as an upload",
-        nameof(headers)
-      );
-    }
-
-    var etagValuesArray = etagValues.ToArray();
-
-    if (etagValuesArray.Length != 1)
-    {
-      throw new ArgumentException(
-        $"Expected Etag header to have a single value but got {etagValuesArray.Length}",
-        nameof(headers)
-      );
-    }
-
-    return etagValuesArray[0];
+    return BlobApiHelpers.ParseEtagHeader(response.Headers);
   }
 
   /// <summary>
diff --git a/src/Speckle.Sdk/Helpers/BlobApiHelpers.cs b/src/Speckle.Sdk/Helpers/BlobApiHelpers.cs
new file mode 100644
index 00000000..c7979567
--- /dev/null
+++ b/src/Speckle.Sdk/Helpers/BlobApiHelpers.cs
@@ -0,0 +1,29 @@
+using System.Net.Http.Headers;
+
+namespace Speckle.Sdk.Helpers;
+
+public static class BlobApiHelpers
+{
+  public static string ParseEtagHeader(HttpResponseHeaders headers)
+  {
+    if (!headers.TryGetValues("ETag", out var etagValues))
+    {
+      throw new ArgumentException(
+        "Response does not have an ETag attached to it, cannot use this as an upload",
+        nameof(headers)
+      );
+    }
+
+    var etagValuesArray = etagValues.ToArray();
+
+    if (etagValuesArray.Length != 1)
+    {
+      throw new ArgumentException(
+        $"Expected Etag header to have a single value but got {etagValuesArray.Length}",
+        nameof(headers)
+      );
+    }
+
+    return etagValuesArray[0];
+  }
+}
diff --git a/src/Speckle.Sdk/Pipelines/Send/Uploader.cs b/src/Speckle.Sdk/Pipelines/Send/Uploader.cs
index 63a17881..1cd4f8f4 100644
--- a/src/Speckle.Sdk/Pipelines/Send/Uploader.cs
+++ b/src/Speckle.Sdk/Pipelines/Send/Uploader.cs
@@ -1,4 +1,5 @@
 using System.Net.Http.Headers;
+using System.Text;
 using Microsoft.Extensions.Logging;
 using Speckle.InterfaceGenerator;
 using Speckle.Newtonsoft.Json;
@@ -54,9 +55,9 @@ public sealed class Uploader : IDisposable
   public async Task Send(Stream fileStream)
   {
     PresignedUploadResponse presignedUploadResponse = await GetPresignedUrl().ConfigureAwait(false);
-    await UploadToS3(fileStream, presignedUploadResponse).ConfigureAwait(false);
+    var etag = await UploadToS3(fileStream, presignedUploadResponse).ConfigureAwait(false);
 
-    await TriggerProcessing().ConfigureAwait(false);
+    await TriggerProcessing(new() { Etag = etag }).ConfigureAwait(false);
   }
 
   private async Task<PresignedUploadResponse> GetPresignedUrl()
@@ -77,7 +78,7 @@ public sealed class Uploader : IDisposable
     return presignedUpload;
   }
 
-  private async Task UploadToS3(Stream fileStream, PresignedUploadResponse presignedUploadResponse)
+  private async Task<string> UploadToS3(Stream fileStream, PresignedUploadResponse presignedUploadResponse)
   {
     _logger.LogInformation("Uploading file to pre-signed url");
 
@@ -100,16 +101,21 @@ public sealed class Uploader : IDisposable
       .ConfigureAwait(false);
 
     uploadResponse.EnsureSuccessStatusCode();
+
+    return BlobApiHelpers.ParseEtagHeader(uploadResponse.Headers);
   }
 
-  private async Task TriggerProcessing()
+  private async Task TriggerProcessing(TriggerUploadRequest request)
   {
     Uri processUri = new($"projects/{_projectId}/modelingestion/{_ingestionId}/uploads/process", UriKind.Relative);
+    string requestBody = JsonConvert.SerializeObject(request);
+    using var content = new StringContent(requestBody, Encoding.UTF8, "application/json");
 
     using HttpResponseMessage processResponse = await _speckleClient
-      .PostAsync(processUri, null, _cancellationToken)
+      .PostAsync(processUri, content, _cancellationToken)
       .ConfigureAwait(false);
 
+    string body = await processResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
     processResponse.EnsureSuccessStatusCode();
   }
 
diff --git a/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs b/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs
index 8ff9a546..11df1420 100644
--- a/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs
+++ b/src/Speckle.Sdk/Pipelines/Send/UploaderDTOs.cs
@@ -1,3 +1,4 @@
+using Speckle.Newtonsoft.Json;
 using Speckle.Sdk.Models;
 using Speckle.Sdk.Serialisation;
 
@@ -12,7 +13,8 @@ internal record PresignedUploadResponse
   public Dictionary<string, string> AdditionalRequestHeaders { get; init; } = new();
 }
 
-internal record ProcessUploadResponse
+internal readonly struct TriggerUploadRequest
 {
-  public required string ingestionId { get; init; }
+  [JsonProperty("etag")]
+  public required string Etag { get; init; }
 }