About Obsol
Every document deserves to know when it is out of date.
Obsol started from a small, familiar problem: you send a CV, a certificate or an offer, then you improve it — and the old copy keeps circulating in inboxes you will never see again. Nobody on the other side can tell it has been replaced.
We fixed that with the simplest proof we could find. Each version of a document gets a SHA-256 fingerprint, anchored on Solana with a timestamp. One permanent link and QR go into the file itself. Whoever holds a copy can check it in seconds and see whether it is current, superseded, or not genuine at all.
No accounts are needed to verify, files are never uploaded to check them, and the record lives on a public chain — so the proof keeps working even without us.
Why the verdict can be trusted
Proof that does not depend on us
Hashed in your browser
A SHA-256 fingerprint is computed locally. Verifying a copy never uploads it.
Anchored on a public chain
Each version is written to Solana with a timestamp no one can edit.
Tamper-evident
Change one character and the fingerprint no longer matches: the copy shows UNRECOGNIZED.
Survives Obsol
The record lives on-chain. Anyone can re-check a fingerprint against it without our servers.
What the record contains
your-document · v2 sha-256 9f86d081…0f00a08 2026-10-07 14:02:11 UTC
- document
- your-document
- version
- v2
- fingerprint
- 9f86d081…0f00a08
- network
- Solana