GustKit

GustKit API

Developers can create an envelope, watch the status, and download the sealed PDF. The website stamp does not use this API.

What you can call

Create an envelope with a PDF or an https URL, a list of signers (name, email, optional role), copy recipients who do not sign, fields (signature, initials, date, or name), and an order (parallel or sequential). Read the status. Download the sealed PDF. Remind pending signers. Cancel an open envelope. Receive webhooks signed with HMAC.

Quota

While billing is off, the monthly cap is not enforced. Set ESIGN_FREE_ENVELOPES_PER_MONTH only if you want a number before you can charge. When billing is on, the default free quota is 20 envelopes a month, then an active Pro plan.

Frequently asked questions

Where is the reference?

Open API docs for curl, JavaScript and Python, and GET /api/docs for the OpenAPI file.

Does a key see the PDF later?

Only during the retention window, and only if the envelope stored it. After that, verification uses hashes and the seal inside the file.