Adding attachments to a row in Smartsheet using a HTTP action in Power Automate

Paul Creedon

I am trying to upload attachments to a Smartsheet row using the HTTP action in Power Automate. Is this possible? The URI is accurate (populated by dynamic content in the flow).

I am receiving this error: "Multipart upload request was invalid. Please check your request headers and payload."

Does anyone have advice?

Thanks!

Paul

ChristianFinke

Hi @Paul Creedon

Yes, you can upload attachments to a Smartsheet row via Power Automate, but the error suggests an issue with headers or body formatting. Double-check that the Content-Type header includes multipart/form-data; boundary=uniqueBoundary123, matching the boundary in your body exactly. Make sure each section in the body starts with --uniqueBoundary123 and ends with --uniqueBoundary123--. Also, ensure the file content is correctly attached. Empty or mismatched content can cause issues. Try with a small test file to rule out file size or content-related problems.

Hope this helps! Let me know if you'd like further assistance.