Provably Fair, Explained: How Crypto Casinos Prove a Game Is Not Rigged

Provably fair means you can check that one round was decided before you bet, not after. It does not mean the game pays 100%. It does not cover the slots in the lobby. Those two limits are the whole subject.

What the casino shows you

Before the round, the casino commits to a secret server seed by showing you its hash. You have a client seed, which you can set yourself. The bet also has a nonce, a counter that stops the same seeds producing the same result twice. The round uses all three. After it, the casino reveals the server seed. You hash it. If the hash matches the one you were shown before the bet, the seed was not swapped. You then run the same function the game uses and the result should match what you were paid.

If the hash does not match, the round was not the round they committed to. That is the signal to stop, screenshot the tab, and leave. It is rare. The ordinary case is that it matches and you still lost, because the game was built to take an edge.

The edge is still there

A checked round can be a losing round. The proof says the draw was fixed in advance. The paytable says how much of your stake comes back over time.

• Plinko publishes 99% at every row count and every risk setting. You can verify the ball. You still pay 1%.
• Mines publishes 99% at one bomb or at twenty-four. The payout table is the price of each extra safe click.
• Aviator pays 97%. That is a third more edge than a 99% original, and predictor apps do not change it, because they cannot see a seed that was hashed before the round.

Treat the percentage as the cost per hour and the verifier as the check that nobody edited your particular bet. They answer different questions.

Where you will find a verifier

On the house originals: dice, crash, plinko, mines, and the games a casino builds itself. Stake, BC.Game and Duel put the tab next to those games. Flagman and Mostbet also carry provably fair titles. The casinos are listed on provably fair casinos.

A Pragmatic slot, an Evolution table, or JetX does not give you a server seed. JetX pays 97%, the same as Aviator, and publishes no seeds to check. Fairness there is the studio’s lab audit, which you cannot rerun from the bet history. Our JetX page says what you can and cannot see.

A check that takes a minute

1. Before the bet, copy the hashed server seed.
2. Set your own client seed if the game lets you. Note the nonce.
3. Play the round.
4. Open the fairness tab and reveal the server seed.
5. Confirm the revealed seed hashes to the value you copied, and that the result matches the payout.

Mines has the longer click-path on its own page, because the number of bombs changes the table you are checking against. The five steps above are the part that never changes.

What people pretend it means

It is not a licence. A site with a verifier and no company name is still a site with no company name. It is not a reason to raise the bet. A 99% game verified perfectly will still grind a balance down. It is not a claim about slots, live tables, or sports. Those sit outside the seed.

We weigh it as one honesty signal next to the licence and the payout record, on how we rate. A casino that refuses to reveal a seed after a round has answered the only question the system is for.

Frequently asked questions