Developer-first API

Build signing into your app in minutes

RESTful API with comprehensive docs. No PhD required.

Lightning Fast

Average response time under 200ms. Your users won't wait.

Secure by Default

OAuth 2.0, rate limiting, and webhook signatures included.

Well Documented

Clear examples in Node.js, Python, Ruby, and cURL.

Simple, powerful API

Send a document for signature in just a few lines of code.

Node.js

const colosign = require('colosign');

// Initialize with your API key
const client = new colosign.Client('your_api_key');

// Create a signature request
const request = await client.signatureRequests.create({
  title: 'Employment Contract',
  signers: [
    { email: 'john@example.com', name: 'John Doe' }
  ],
  files: ['contract.pdf']
});

console.log('Request sent:', request.id);

cURL

curl -X POST https://api.colosign.com/v1/signature-requests \
  -H "Authorization: Bearer your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "title": "Employment Contract",
    "signers": [
      {"email": "john@example.com", "name": "John Doe"}
    ],
    "files": ["contract.pdf"]
  }'

Core endpoints

POST/v1/signature-requests

Create a new signature request

GET/v1/signature-requests/:id

Get signature request status

GET/v1/documents/:id/download

Download signed document

DELETE/v1/signature-requests/:id

Cancel a signature request

Ready to start building?

Get your API key and start integrating in minutes.