E-signatures
by the sip.

The e-signature API built for AI agents and developers. One line of code. Pay per document. No subscriptions, no seat licenses, no enterprise sales calls.

Get API Key Read Docs
sign.js 
// That's it. One call.
const envelope = await sipsign.sign({
  document: "contract.pdf",
  signers: [
    { email: "alice@co.com", name: "Alice" },
    { email: "bob@vendor.io", name: "Bob" }
  ],
  brand: "your-company"
});

// Cost: $0.10
// Time to integrate: 5 minutes

Cost per envelope

DocuSign API
$4.80
per envelope
+ $600/yr subscription minimum
BoldSign
$0.75
per envelope
+ monthly plan required
SignatureAPI
$0.25
per document
Usage-based
SipSign
$0.10
per envelope
No subscription. No minimums. Just sign.

Built for machines that build things

Every e-sign API was designed for humans clicking buttons. SipSign is designed for AI agents writing code.

MCP

AI-Native Discovery

Published as an MCP server. When an AI agent needs to sign a document, it finds SipSign automatically. No manual integration needed.

API

One-Line Integration

A single function call with all parameters. No OAuth dance, no webhook configuration, no 47-page integration guide.

$$$

Pay Per Sip

$0.10 per envelope. No monthly subscription, no annual contract, no seat licenses. Process 1 document or 100,000.

OSS

Open Source Core

Built on battle-tested open source signing engines. Audit the code, verify compliance, extend as needed.

WHL

White-Label Ready

Your brand on every signing page. Your domain, your logo, your colors. SipSign stays invisible to your customers.

MKT

Marketplace Distribution

Coming to Databricks and Snowflake marketplaces. The first e-signature API available where data teams actually work.

The API that AI discovers

AI coding agents generate thousands of applications daily. Those apps need e-signatures for contracts, approvals, onboarding, compliance.

SipSign publishes as an MCP tool server. When Claude, Cursor, or any AI agent needs document signing, SipSign appears in its toolset. Zero configuration. Zero friction.

// MCP Tool Discovery { "name": "sipsign_send_envelope", "description": "Send a document for legally binding e-signature", "parameters": { "document_url": "string", "signers": "array", "brand": "string (optional)", "callback_url": "string" } }

Contracts shouldn't cost more than the paper they replaced.

SipSign makes document signing as cheap and simple as it should have been from the start. Built for the age of AI, priced for the real world.

Start Signing — Free to Try