E-signatures for AI agents and humans
Send a legally binding signature in one API call
API-first e-signatures. Prepaid credits, no per-seat fees. Send your first document in one curl.
Free tier included · No credit card required · Credits never expire
$ curl -X POST https://api.zsign.io/v1/documents/send \
-H "Authorization: Bearer your_api_key" \
-F "file=@contract.pdf" \
-F 'recipients=[{"email":"john@company.com","name":"John Doe"}]'
# Response
{
"document_id": "doc_abc123",
"status": "sent",
"signing_url": "https://sign.zsign.io/abc123"
}Features
Built for developers, not procurement
Everything you need to send, sign, and track documents.
API-first design
Every action is a REST call. Send documents, check status, and pull signed PDFs without touching a UI.
POST /api/v1/documents/sendNo per-seat pricing
Pay for envelopes, not people. Add unlimited teammates at no extra cost.
Prepaid envelopes, as low as 9.9¢ in volume. See pricingCourt-ready audit trail
Every view, send, and signature is captured with IP, timestamp, and a SHA-256 document hash. Tamper-evident and exportable.
Template links
Share a reusable link and collect signatures without writing code.
AI contract insights
Optional summaries flag key terms and obligations before anyone signs.
Your brand, not ours
Remove the zSign badge, host signing at your own domain, and send from your own email domain.
See white-label pricinghttps://sign.yourbrand.com/abc123Pricing
Pay for envelopes, not seats
Prepaid credits. 1 credit = 1 signed envelope. No subscription required, no per-seat fees.
White-label
Your brand across signing, emails, and documents.
- Your logo on the signing page
- Your brand color across signing and emails
- Remove the zSign badge
- Signing at your own domain
- Send from your email domain
- 100 envelopes/month included
Credits never expire. Agents and CI can buy programmatically: POST /api/v1/credits/checkout.
Stop paying per seat to send a signature.
Prepaid envelope credits, no subscription required, and an API you can integrate in an afternoon.
Get your API key