return_envelope_id is an optional integer ID of an active Return Envelope owned by the document's client.

For creation or upload, omit, pass null, or pass 0 for no Return Envelope. For updates, omit to preserve the current assignment; pass null or 0 to clear it.

In a document upload, a CSV return_envelope_id column overrides the global request value for that row. See the linked endpoint documentation for input validation and response options.

The Checkissuing API is a powerful tool allowing for the easy integration between your back-office systems and the Checkissuing platform.

• Fully automate your funding source and payment management utilizing our many API methods.
• Use standard HTTPS POST requests within your programming language of choice or through various command line tools.
• Responses are returned in JSON format for maximum flexibility and ease of parsing/use.
• Test your code with our fully functional sandbox environment to ensure accuracy prior to going live.

All API endpoints will be appended to the Base URL below: