authii — proof, not promises

Signatures that mean something.

Send a contract. Each signer taps their fingerprint. You get a sealed document that holds up in court — and we never see what's inside it.

Sign up freeI have an account →Verify a document
Or — skips the email step.
why teams switch

Sign in seconds. Verify forever. Yours, end to end.

01 · speed

Most contracts close in minutes.

Your signers don't need an account, a download, or training. They open the email, tap their fingerprint, and they're done. No passwords to reset, no codes to wait for, no "please install the app."

02 · privacy

We literally can't read your documents.

Choose end-to-end encryption and every PDF is locked on the sender's device before it ever reaches Authii. We hold scrambled bytes that even we can't open — not for a court order, not for a breach, not ever.

03 · permanence

The signed PDF stands on its own.

When everyone has signed, you get a sealed PDF that any reader can open in any year. The proof of who signed, and when, travels inside the document itself — no trip back to our servers required, no Authii account needed for the counterparty to verify.


how it works

One fingerprint. That's the whole flow.

  1. 01You drop a PDF, pick signers by email, and click send.
  2. 02Each signer opens the email and taps their fingerprint sensor — that's the signature.
  3. 03When the last person signs, the document is sealed automatically and emailed to everyone.
  4. 04Open it on any device, any year. The signatures still verify.

$0

Per-signature fee on the free plan. Send a hundred contracts a month and the bill stays at zero.

<30s

The time it takes a first-time signer to go from clicking the email to done. No account creation, no training.

Forever

The lifetime of a sealed document. Authii could disappear tomorrow and yours would still verify in any PDF reader.