Signature

Send a document for signature and get back an executed copy plus an audit trail of exactly what happened. One API call: each signer gets their own private link, signs in a browser with no account, and you collect the countersigned PDF.

• Hand over the document as a public https PDF URL, raw base64 bytes, or markdown that gets typeset for you — exactly one, because silently ignoring a field is how the wrong document gets signed
• The bytes are hashed with sha256 the moment they arrive and never rewritten. The executed copy COPIES those pages into a new PDF and appends a certificate of completion, so "is this the document they signed?" is answered by hashing it
• The audit trail records only what the server observed: timestamps in UTC, the client IP and user-agent as sent, the name each signer typed, their explicit consent, and the document hash they were served
• It also names what it does NOT record — identity is never verified, nothing is notarised or witnessed, and an IP address is never presented as a location
• This produces an executed record with an audit trail. It is not legal advice and makes no claim of ESIGN, UETA or eIDAS qualification. Every API response carries legalQualification: "none"
• Signers get one private link each, 256 bits of entropy, stored only as a hash. Signing order is supported: a later group is only invited once the earlier one has signed
• 15 credits to send, 10 more only if and when every signer signs. Polling, reading the audit trail, downloading an executed copy and withdrawing an envelope are all free
• Agent-native from day one: sgn_live_ REST keys, an MCP server (works with the Ounie AI Team via ?api_key=), keyless x402 pay-per-call in USDC, and the fleet master key

{
  "mcpServers": {
    "ounie": {
      "url": "https://mcp.ounie.com"
    }
  }
}

{
  "mcpServers": {
    "sign": {
      "url": "https://sign.ounie.com/api/mcp"
    }
  }
}