Duel.com provably fair verifier

Why use an independent verifier?

Duel has its own provably fair verifier in your account settings. Our tool does the same math independently. The advantage: you do not have to trust Duel's verifier code. Open-source verification keeps the operator honest.

The math is identical (SHA-256 is SHA-256). The trust difference is purely whose JavaScript you run.

What this verifier proves

If the SHA-256 hash of the revealed server seed equals the previously published hash, the operator committed to that specific seed value before the round. They could not have substituted a different seed later, substitution would produce a different hash.

This is the core provably fair guarantee. Combined with the deterministic mapping algorithm (which Duel publishes), it means every round result was set the moment the seeds were locked in.

How to get the values to verify

1. Open Duel.com → Account → Provably Fair.
2. Note the current server seed hash (this is the public commitment).
3. Play some rounds. Note the nonce and result of any round you want to verify.
4. Click "Rotate server seed". Duel reveals the previous server seed and switches to a new one.
5. Paste server seed, hash, client seed, and nonce into our verifier above.

What this verifier does NOT do

• It does not re-derive the actual game outcome, each game (Crash, Dice, Plinko, Mines) uses a different mapping algorithm from the hash to the result. For full outcome verification, use Duel's in-app verifier or a game-specific implementation.
• It does not verify Duel's RNG quality, provably fair proves no retroactive manipulation, not that the seed itself is random.
• It does not protect against attacks on the client-side. If your browser is compromised, all bets are off.