zSign
Send documents for e-signature from AI assistants, track signers, and download sealed, signed PDFs.
Hosted MCP Server
npx add-mcp 'https://zsign.io/mcp'Installs into Claude Code, Codex, Cursor and more
Documentation
E-signatures without seats or sales calls.
Send from the dashboard, your app, or your AI assistant. Prepaid envelopes, no per-seat fees.
ESIGN & UETA compliant SHA-256 tamper-evident audit trail
3 free envelopes to start after email verification · No credit card required · Credits never expire
Last updated October 24, 2026
# contract.pdf must contain fields such as {signature*:signer}
curl -X POST https://zsign.io/api/v1/documents/send \
-H "Authorization: Bearer your_api_key" \
-F "file=@contract.pdf" \
-F 'recipients=[{"email":"you@example.com","name":"Your Name","role":"signer"}]'
# Response (201, abbreviated; example values)
{
"document_id": "550e8400-e29b-41d4-a716-446655440000",
"session_id": "660e8400-e29b-41d4-a716-446655440000",
"signing_urls": [{
"recipient_email": "you@example.com",
"signing_url": "https://zsign.io/sign/eyJ..."
}]
}
Features
Send, sign, done. No seats, no sales calls.
Send from the dashboard, your app, or your AI assistant. Pay per envelope, never per person.
No per-seat pricing
Pay for envelopes, not people. Add unlimited teammates at no extra cost.
Prepaid envelopes, as low as 29.7¢ in volume. See pricing
Send from anywhere
Send an envelope from the dashboard, Zapier, the REST API, or the MCP server at zsign.io/mcp.
Built to automate
Every action is a REST call. Send documents, check status, and pull signed PDFs without touching a UI.
POST /api/v1/documents/send
Court-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.
Your brand, not ours
Remove the zSign badge, host signing at your own domain, and send from your own email domain.
https://sign.yourbrand.com/abc123
Pricing
Pay for envelopes, not seats
1 credit = 1 envelope send. Credits never expire. No subscription required, no per-seat fees.
Starter
$27
50 envelopes
54¢ per envelope
Most popular
Growth
$87
250 envelopes
34.8¢ per envelope
Scale
$297
1000 envelopes
29.7¢ per envelope
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
$49/month
Credits never expire. Agents and CI can buy programmatically: POST /api/v1/credits/checkout.
FAQ
Questions, answered
Pricing, legal validity, integration, security, and the referral program.
Pricing & credits
How does pricing work, and is there a subscription?
No subscription required. 1 credit = 1 envelope send. Credits never expire. The credit is charged when the envelope is sent, not when signing finishes. Drafts cost no credit until sent. A failed send reverses its charge. A void refunds the send credit only if no recipient has viewed, signed, or declined; the first qualifying resend after a signer requests changes is free. Buy a pack when you need one: Starter is $27 for 50 envelopes (54¢ each), Growth $87 for 250 (34.8¢ each), Scale $297 for 1,000 (29.7¢ each). Add as many teammates as you want at no extra cost, since you pay for envelopes, not seats.
What happens when I run out of credits?
Sends return 402 with {"error": "insufficient_credits"} and nothing is delivered; the debit happens before the envelope goes out, so you’re never charged for a send that didn’t happen. Top up with POST /api/v1/credits/checkout. The credits checkout endpoint returns a Stripe Checkout URL. The buyer completes payment through Stripe Checkout before purchased credits are available.
Legal validity
Are signatures from zSign legally binding?
Yes. Signers explicitly consent to sign electronically, consistent with the U.S. ESIGN Act, UETA, and similar laws elsewhere, and every completed envelope ships with a tamper-evident completion certificate. We’re not a law firm and can’t guarantee enforceability in every jurisdiction, so that call is yours to make for your documents.
Are there documents I shouldn't sign electronically?
Some document types aren’t eligible for e-signature under applicable law, such as wills and certain notarized instruments. zSign provides the signing infrastructure; deciding whether e-signature is appropriate for a given document is the sender’s call.
API & AI agent integration
How do I get an API key?
POST /api/v1/signup returns an account and a zs_live_ key in one call. API or MCP signup creates an account and API key with 0 credits. Email verification grants 3 free credits, or 25 for an eligible referral signup. No credit card is required for the free credits.
What does "built for AI agents" actually mean?
The remote MCP server is at zsign.io/mcp. Agents can prepare documents, send envelopes, track status, and download completed PDFs through REST or MCP. A draft can be left for approval before sending. Recipients review, consent, and sign for themselves; an agent does not sign on their behalf.
Security & white-label
What do you record, and what happens to my documents?
Every envelope carries an audit trail: signer name and email, IP address, browser, view and signature timestamps, consent, and a SHA-256 hash of the document, all tamper-evident and exportable. Documents are encrypted in transit and stored in access-controlled cloud storage. We never sell personal data.
What does the white-label plan include?
$49/month puts your brand everywhere zSign would otherwise appear: your logo and color on the signing page and emails, the zSign badge removed, signing hosted at your own domain, and email sent from your own verified sender. It includes 100 envelopes/month; the credit packs above stay available if you need more.
Referrals
How does the referral program work?
Every account gets a referral link automatically, no application needed. Someone who signs up through your link and verifies their email receives 25 free credits instead of the usual 3, and you earn 30% of every payment they ever make, on credit packs and white-label subscriptions alike, for as long as their account is active. Get paid to send signatures.
How do I get paid?
Commission settles quarterly once your balance clears $25 (US payouts only). Below that, or if you don’t want to wait, convert your balance to zSign credits any time at a 1.5x bonus, instant, no minimum. A $10 balance, for example, converts into 43 zSign credits right away, spendable the same as purchased credits: 43 envelopes sent through the dashboard or API, no expiration.