Upload a document as an original so you can send it for signature or sign it yourself. Send it as multipart/form-data, up to 25 MB. The id you get back is what the envelope endpoints take as a source. An empty file returns 400 empty_file. A file named .pdf that isn't a valid PDF returns 400 invalid_file. A corrupted file in another format can still return 500. A password-protected PDF uploads, but you can't send it, so remove the password first.
Upload a new document as an original to Signeasy to use it for signing (either yourself or others) via the envelope APIs.
The file can be gzip compressed to make the upload faster. In such cases Content-Encoding header must be passed as gzip for the server to recognise the compression. Any request without the Content-Encoding header is counted as an uncompressed file upload which may lead to a server error.