The Signater API lets your systems create, send and track signature workflows without anyone opening the web app. Everything the platform does with an envelope — assembling documents, collecting signatures, enforcing identity checks, returning the signed file and its audit certificate — is available over HTTP.
Documents — upload files, or generate them from a template with fields filled in.
Signers — define who signs, in what order, with which identity checks, and how each one is contacted.
Sign marks — place signatures, initials and form fields (text, dates, currency, checkboxes, dropdowns, file attachments) at exact coordinates on a page.
Vaults — organize envelopes and templates, and control who inside the account can reach them. Every envelope needs one, and a new account has none.
Contacts — reuse signer details across envelopes.
Results — fetch the original file, the signed file and the audit certificate.
The API does not manage users, accounts or billing. Those live in the web app.
The API and webhooks are available on the Business and Enterprise plans, in both production and sandbox. If your requests come back with 403 and a message about the plan, that is what it means.
Instead of polling, subscribe to Webhooks and let Signater tell your system when an envelope is published, viewed, signed, rejected or expired. Delivery is retried automatically and the payload always carries the envelope id, so you can fetch the current state from the API.
The Quickstart takes you from an empty account to a published envelope in five requests. If you would rather understand the model first, read Concepts.