Send a legally binding signature in one API call

No subscription required. zSign runs on prepaid credits: 1 credit = 1 signed envelope, and credits never expire. 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.

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, which your agent or CI can call programmatically without a human touching a billing page.

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.

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.

POST /api/v1/signup returns an account and a zs_live_ key in one call, with no sales call and no verification queue. Verify your email and 3 free envelope credits land automatically, no credit card required; after that, top up with the packs above whenever you need more.

There’s a remote MCP server at zsign.io/mcp exposing the whole lifecycle as tools: create an account, check pricing, buy credits, send an envelope, check status, download the signed document. An agent can go from nothing to a signed PDF unattended, and it’s a thin adapter over the same REST API, so MCP behavior can never drift from a plain curl call.

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. AI summaries are optional and can be disabled per document, and we never sell personal data.

$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.

Every account gets a referral link automatically, no application needed. Someone who signs up through your link starts with 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.

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 signed envelopes sent through the dashboard or API, no expiration.