ZAMBO.

Seal a deliverable

Drop a file or paste text below. This page computes its SHA-256 fingerprint right here in your browser and shows it with the time and the file name. Save the fingerprint. Days or months later, run the same file through the checker at the bottom: if the fingerprint matches, the bytes are exactly the ones you fingerprinted. Nothing is uploaded. The file never leaves your machine.

Fingerprint a file or text

Drop a file here or click to choose one

Reports, exports, images, archives: anything you are about to hand over.

Or paste text instead:

What the fingerprint proves, in one line: the saved bytes match, so any later change shows. Change one byte and the fingerprint is completely different. It proves nothing about whether the work is good or right, only that it is the same work you fingerprinted.

Check a file against a saved fingerprint

Paste a fingerprint you saved earlier, then drop the file you want to test.

Drop the file to check or click to choose one

No file chosen yet.

A fingerprint you keep vs a receipt that is kept for you

The fingerprint above is a fingerprint you keep yourself. That is genuinely useful, and it has a limit: if you lose the fingerprint, or the person receiving the work never got it, there is nothing left to check against.

Work done through Zambo gets the kept-record version automatically. An agent receipt is a record of one ai agent tool call that anyone can check: it keeps the exact saved bytes and their sha-256 digest, and it proves the result was not changed since it was saved, not that it was right. Zambo keeps that record on the server for every call, and anyone you hand the link to can check it at zambo.dev/verify. No fingerprint files to manage, no trust-me: the record is the check.

The short route in is zambo.dev/add, one page per AI. Connect any MCP client to zambo.dev/mcp with no key: 20 free calls per day, then a Day Pass at $0.99 USDC on Base for 24h or a Zambo Pass at $29 for 30 days. Zambo is the verifiable work layer for AI, and its flagship product is HANDOVER.

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