XXXIIILPS-1 PROOF

Got an idea? Prove it's yours.

Drop in a file: a manuscript, song, design, contract or invention notes. We record its fingerprint on two public blockchains, so anyone can check that it existed, unchanged, on this date.

Drop a file here or click to choose
Your file is fingerprinted in your browser. Up to 25 MB.

Private by default: only the fingerprint leaves your computer. Your file never does.

$49
Founding price, 50 left · then $99

What you get

  • A public proof page and printable certificate
  • Anchor on Polygon within about 5 minutes
  • Bitcoin timestamp within a few hours
  • A proof file anyone can verify without us

Private by default

We never need your file, only its fingerprint. Nobody can rebuild your work from a fingerprint, but anyone holding the file can prove it matches.

For businesses and AI agents

Prepaid API keys for volume, and x402 pay-per-proof in USDC. See the API.