Introduction

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.

Base URL

https://api.signater.com

Every endpoint in this reference is relative to that host. All requests are authenticated with the x-api-token header — see Authentication.

What you can do

Envelopes — create, update, schedule, publish, hold, cancel and restore signature workflows, and list them across vaults with filters.

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.

Reports — the envelope, signer, team, template, sealing and blockchain reports, the home dashboard and the history of what signers did.

Usage — the envelope balance, its statement, who consumed it and the storage of each vault.

Members — the account's members and the invites waiting for an answer.

Webhooks — the receivers you configured and their delivery history.

Reports, usage, members and webhooks are for administrators, as in the app; the dashboard is open to every member. The API reads members and invites but does not change them, and it does not handle billing. Those changes live in the web app.

Requirements

The API, webhooks and the MCP server 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.

Webhooks

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.

AI assistants

An assistant such as Claude, ChatGPT or Cursor can work with your account through the MCP server: it reads envelopes and reports, drafts and publishes envelopes, and answers questions about the account in plain language. It uses the same account, permissions, plan and rate limit as the API, with a credential of its own.

Start here

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.

Base URL#

What you can do#

Requirements#

Webhooks#