$ cd ~/work/solnotary
SolNotary
A web app that proves what someone knew, and when. It seals a text by writing only its hash to Solana, then publishes the text for an exact crypto payment, on a page anyone can verify.
00//the walkthrough
3 screens · tapclick to enlarge
01//the problem
Predictions, sealed bids and ideas are only worth something if you can prove later that they came first, without giving them away early. Screenshots and emails can be faked, and posting the text publicly reveals it. The client wanted a commitment that a public blockchain can vouch for, fast and cheap, with publishing as the paid step.
02//the approach
Next.js 16 with Solana web3.js. Sign-in is a wallet signature checked on the server. The server hashes the text, a live BTC, ETH and SOL price snapshot and a secret salt with SHA-256 and writes only the hash to Solana as a memo transaction. Supabase keeps the records behind row-level security, so a sealed text can't be read with the public key.
03//what I built
Wallet sign-in
A one-time challenge signed by the wallet and checked with ed25519; no passwords or email.
Sealed on-chain
Only the hash goes on Solana, as a memo transaction confirmed in seconds.
Paid reveal
An exact payment in SOL, USDC or USDT with a reference memo publishes the text.
Verify in the browser
Public pages reveal the text and salt and recompute the hash in the visitor's own browser.
Admin overview
Every record and payment, read-only, without ever showing sealed text.
// the impact
SolNotary is a client project. The live demo runs on Solana devnet: every transaction is real and opens in Solana Explorer, but it uses test SOL with no value. A hash on a blockchain shows a text existed at a time; it is not a legal notarization. The 2-minute video above shows a verified record, a new notarization and the admin overview.
// let's build yours
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