Developers API

Add e-signatures to your product

Integrate signing into your app with a type-safe REST API, SDKs, webhooks, and MCP. Test for free in sandbox — pay per signature in production.

OpenAPI spec with HTTP signature authentication Free sandbox — integrate without consuming credits Documents stay confidential even during signing
# Create an envelope from a file
curl -X POST \
  $PROXY_URL/public/envelope/create-from-file \
  -H "Authorization: Bearer $ACCESS_KEY:$SECRET_KEY" \
  -F "envelopeTitle=Service Agreement" \
  -F "[email protected]"

# Send it for signature
curl -X POST \
  $PROXY_URL/public/envelope/send \
  -H "Authorization: Bearer $ACCESS_KEY:$SECRET_KEY" \
  -H "Content-Type: application/json" \
  -d '{"envelopeUuid": "env_123"}'
Made in France 🇫🇷GDPR-readyConfidential computing

Built for teams who can't compromise on security or speed

Most e-signature APIs expose documents to the provider. Subnoto keeps agreements confidential during processing — so you ship faster without adding compliance risk.

Ship in hours, not weeks

Full OpenAPI specification, type-safe SDKs, and step-by-step tutorials. Get an e-signature feature in minutes, not hours.

Stay compliant by default

Legally binding signatures in Europe and the US. Audit trails, eIDAS-aligned evidence, and GDPR-ready architecture out of the box.

Protect sensitive agreements

Confidential computing and end-to-end encryption keep contracts private during signing — including from Subnoto itself.

Everything you need to integrate

REST API

Full OpenAPI specification with type-safe endpoints, built-in encryption, and HTTP signature authentication.

Type-safe SDKs

Official TypeScript and Python SDKs with encryption and authentication handled for you.

Real-time webhooks

Get notified the moment envelopes are signed or completed, so your systems stay in sync.

MCP server

Let AI assistants like Claude and Cursor create and send envelopes through natural language.

How to get started

Create your Subnoto account

Sign up for free and explore the web app. Subscribe to Pro or Ultimate when you're ready for production API access.

Generate API keys and test in sandbox

Enable sandbox mode on a workspace and integrate freely — no credits consumed while you build and validate.

Go live with pay-per-signature pricing

Buy API credits at €0.40 per signer. Credits never expire. One credit per signer on API-sent documents.

Simple, transparent pricing

Test for free. Pay only when you send signatures in production.

Pro or Ultimate subscription required for production API access

Sandbox

Free
€0 / signature
  • Unlimited test calls
  • No credit card required
  • Same API surface as production
Get started

Production

Pay as you go
€0.40 / signature
  • €0.40 per signer
  • Credits never expire
  • Included with Pro or Ultimate
Sign up for Pro

What our customers say about Subnoto

Subnoto reviews on Capterra

Rated 5/5 on Capterra

Non-profit
5/5

"Overall, Subnoto is a very compelling tool from a human-sized team with attentive, responsive support that does its best. We value Subnoto for how feature-rich, secure, available, comfortable, and performant it is. It genuinely helps us in our day-to-day work and it is excellent!"

Constantin C. Treasurer
Telecommunications
5/5

"Subnoto is my go-to for anything I need to sign, both personal and work admin stuff. It saves me from the print/sign/scan routine."

Matthew A. Senior Project Manager
Entertainment
5/5

"Subnoto is easy and quick to use. Creating signers is intuitive, and the automatic/manual reminder system is brilliant."

Joffrey G. President
Manufacturing
5/5

"Great experience, with a smooth and pleasant interface. It is simple and very quick to get started."

Pierre P. Systems, Network and Cybersecurity Engineer
Internet
5/5

"Very happy to have found this company and to work with them. I will integrate Subnoto e-signatures more often into the SaaS products we build."

Adrien C. Managing director

Frequently asked questions

Ready to integrate?

Start in sandbox for free. No credit card required to explore the API.