post
https://api.mercury.com/api/v1/recipient//attachments
Upload a tax form attachment for a recipient. The file is uploaded via multipart/form-data. Supported file types include PDF, images (PNG, JPG, GIF), and common document formats. The attachment will be associated as a tax document for the recipient.
Successfully uploaded attachment. Returns attachmentId and downloadUrl.
Bad request. Either no file was uploaded or the filename exceeds the 299 character limit.
Recipient not found
File too large. Maximum file size is 32MB.
Unsupported file type. Potentially dangerous file extensions (e.g., .exe, .bat) are not allowed.