I have an envelope that consists of compositeTemplate. There are 2 inlinteTemplates, first one contain some documents. I want to replace one of the documents. Is there any REST API that I can use and send JSON to replace the document? Example: Documents 1, 2, 3 are in a composite template. Envelope has been sent to recipient. Document 3 is a HTML document which needs to be replaced by another HTML document. I found a post that says how to replace but I don't know which REST API to call to implement this. DocuSign Rest API to replace single template document
With no clue to replace, I have tried following but did not work PUT /v2.1/accounts/{accountId}/envelopes/{envelopeId}/attachments
You do need a PUT but to a slightly different endpoint.
see documentation here - https://developers.docusign.com/esign-rest-api/reference/Envelopes/EnvelopeDocuments/update
PUT /v2.1/accounts/{accountId}/envelopes/{envelopeId}/documents/{documentId}
Now finding the documentId may require you to make a GET call first to retrieve the envelope and all the documents.