Debugging the Envelope JSON
If you're having issues sending an envelope signing request to the Docusign API it can be helpful to inspect the contents of the JSON payload that is being sent to other Docusign API. We've added a flag in the fmESignature Link v2 file so you can log the last JSON payload that was sent for a Request by clicking the Log Envelope Request checkbox highlighted here:

With this option enabled after the request has been sent to Docusign you will see the contents of the JSON payload on the Envelope JSON tab:

You can also use the FileMaker Pro Script Debugger and Data Viewer to debug the script and view the result of various variables and fields. Regardless of the Log Envelope Request setting we also store the JSON for the last envelope request that was sent in a FileMaker global variable named:
$$jsonDebug
which you can view using the the Data Viewer. This is automatically updated every time an envelope is sent to DocuSign.
DocuSign also has a way of logging requests via the API – see here for more details on how to enable logging and download the DocuSign logs.