An e-signature API lets developers add legally binding electronic signatures to their own software programmatically. Instead of a manual web app, your code creates documents, collects signatures, and receives sealed, audited files over REST — so signing becomes a feature inside your product.
Last updated June 2026
An e-signature API exposes the entire signing workflow as programmable endpoints. Instead of a person uploading a document and clicking through a web app, your code creates the document, defines who signs and where, dispatches signing links, and receives the finished, sealed file — all over HTTP.
That means signing becomes a feature inside your product, not a separate tool your users have to leave for. A lending app, an HR platform, or a marketplace can all collect signatures inline, branded as their own.
Most e-signature APIs follow the same lifecycle: authenticate (usually OAuth2 client credentials or an API key), create an envelope containing the document plus signer and field definitions, send it to generate per-signer signing links, and then receive a webhook when signing completes.
On completion, the service flattens the signed fields into the PDF, appends an audit record, and applies a digital seal so any later change is detectable. Your application is notified via webhook and can download the sealed file — no polling required.
A good e-signature API is genuinely API-first: documented REST endpoints with an OpenAPI spec, service-to-service authentication, signed webhooks, and idempotent requests. It should also be legally defensible — a tamper-evident seal plus an audit trail capturing consent, identity verification, timestamps, and IP for each signing event.
Transparent, self-serve pricing with a free tier matters too: it lets you build and test a full integration before committing. GetSigned was designed around exactly these principles.
An e-signature API is a set of REST endpoints that let developers add legally binding electronic signatures to their own application. Your code creates a document with signers and fields, sends signing links, and receives a sealed, audited file via webhook — replacing a manual signing UI with programmatic calls.
A signing web app is used by a person through a browser. An e-signature API is used by your software: it embeds the signing workflow directly into your product so users never leave it, and it automates document creation, sending, and sealed-file retrieval.
Yes, when the workflow captures intent, consent, attribution, and a tamper-evident record. GetSigned is built for PIPEDA, ESIGN, and UETA and seals every completed document with a PKCS#7 signature plus a hash-chained audit log.
Yes. GetSigned offers a free Starter tier with full REST API access, PKCS#7 sealing, OTP identity verification, and webhooks, with 5 envelopes per month — enough to build and test a complete integration.
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