notaros vs. OpenTimestamps.
OpenTimestamps is a superb open standard for Bitcoin timestamps — and notaros is built on it, not against it. The question is not which to trust, but how much you want done for you.
notaros uses OpenTimestamps
The Bitcoin tier of every full-service notarization is an OpenTimestamps commitment. Your certificate carries a standard .ots proof you can verify with the ordinary ots client — no notaros involved. The free verifier even checks bare .ots proofs for files notaros never touched. There is no lock-in by design.
What notaros adds
- A Base smart-contract anchor alongside Bitcoin — fast, low-cost confirmation and a record you can read with a single
notarizedAt(hash)call. - Fronted cost and gas. No wallet, no crypto, no running a client — pay $25 and it is done.
- A signed PDF certificate and a hosted verifier page, plus a downloadable offline verifier you keep.
- Developer channels — REST, MCP, and A2A — with signed, machine-readable receipts.
| notaros | OpenTimestamps (direct) | |
|---|---|---|
| Bitcoin anchor | Yes (via OTS) | Yes |
| Base smart-contract anchor | Yes | No |
| Cost / gas fronted | Yes | You run the client |
| Signed PDF certificate | Yes | No |
| Hosted + offline verifier | Yes | CLI verify |
| OTS-compatible / no lock-in | Yes | Yes |
| Price | $25 / document | Free |
Use OpenTimestamps directly when…
…you want a free Bitcoin timestamp, are comfortable running the client, and do not need a Base anchor, a certificate, or hosted verification. It is a great tool and we recommend it. Use notaros when you want a turnkey, dual-anchored, court-minded proof with a certificate and verifiers — without touching a wallet.