1. Upload your PDF
Send your document with recipients and field placement details in one request.
E-Signature API for Developers and AI Agents
Send legally binding documents for signature in one API call. Pay $0.10 per envelope. No subscription.
One API call. Pay per document. No subscriptions, no seat licenses, no enterprise sales calls.
Works with Claude, GPT, and any MCP-compatible agent
How it works
2. Recipients sign
Recipients receive a signing email instantly and complete the document securely.
3. Track completion
Receive webhook notifications as each signer completes their step.
Built for machines that build things
A practical e-signature API with strong defaults, clear behavior, and full control for product teams and autonomous agents.
Sequential signing
Send to multiple recipients in order, or switch to parallel signing when speed matters.
MCP native
Works as a tool for Claude and any AI agent that supports MCP.
x402 payments
Agents can pay autonomously with crypto, no account required.
Webhook events
Get real-time status updates for document creation, opens, and completion.
Idempotency
Safe retries prevent duplicate contracts, even across network failures.
Sandbox mode
Test with realistic responses at no charge and no recipient emails.
Complete field control
Place signature, initials, date, text, checkbox, radio, and dropdown fields anywhere on any page. Sequential or parallel signing. Every open-source signing capability, accessible via one API.
Full open-source API passthrough
Verafirma exposes the complete API surface: every recipient role, field type, signing configuration, and document option.
Recipient roles
- SIGNER
- APPROVER
- VIEWER
- CC
- ASSISTANT
Field types
- SIGNATURE, INITIALS, DATE, NAME, EMAIL
- TEXT, NUMBER, CHECKBOX, RADIO, DROPDOWN
Signing order options
- PARALLEL
- SEQUENTIAL
Document configuration options
- Custom email subject and message
- Redirect URL after signing
- Recipient expiration dates
- Multi-language support
- Signature type controls
- Recipient authentication controls
Pricing
$0.10 per envelope
No monthly fee. No seat license. No minimums.
Crypto (x402)
Pay per call, no account needed, designed for autonomous AI agents.
Prepaid Credits
Fund with Stripe, issue API keys, and manage usage in the dashboard.
| Provider | Per Envelope | Subscription |
|---|---|---|
| DocuSign API | $4.80 / envelope | $600 / year minimum |
| Verafirma | $0.10 / envelope | No subscription |
What counts as one envelope?
One PDF sent to one or more recipients for signing.
Is there a free tier?
Yes. Use test_mode: true to send unlimited test envelopes at no charge.
Do I need an account?
No. Pay with crypto and start instantly without signup.
Legally binding in 180+ countries
Verafirma signatures comply with electronic signature laws worldwide. Every envelope includes a full audit trail: signer identity, timestamp, IP address, and device, meeting evidentiary requirements across frameworks.
United States
ESIGN Act (2000) - legal validity for e-signatures in interstate commerce.
UETA - adopted by 49 states, equal legal weight to handwritten signatures.
European Union
eIDAS - EU Regulation 910/2014. Produces SES-compliant signatures.
United Kingdom
Electronic Communications Act 2000 - recognizes e-signatures as binding.
Canada
PIPEDA - supports electronic document and signature validity.
Switzerland
ZertES - Swiss federal electronic signature compliance framework.
Electronic signature requirements vary by jurisdiction and document type. Consult qualified legal counsel for your specific use case. This does not constitute legal advice.
Trust signals
Audit trail
Complete records on every document event.
ESIGN aligned
Legally binding signatures with evidence suitable for compliance workflows.
Secure retention
Choose document retention windows that match your policy and risk model.
Open-source foundation
Built on the best of open-source e-sign infrastructure.
Contracts shouldn't cost more than the paper they replaced.