How provably fair works
Three inputs decide the result of a provably fair game:
- Server seed. Chosen by the casino and kept secret, but its hash is shown to you before you bet.
- Client seed. Chosen by you, or generated for you and changeable.
- Nonce. A counter that goes up by one with every bet.
The game combines the three and turns the combination into a result: a dice roll, a crash point, a plinko path. When you rotate to a new server seed, the old one is revealed. You can then recompute every bet you made with it and check that each result matches.
Checking a round, step by step
- Before playing, note the hashed server seed shown in the fairness settings.
- Set your own client seed if you want; any text works.
- Play. Each bet records the nonce.
- Rotate the seed. The casino reveals the old server seed.
- Check that the revealed seed hashes to the value you noted in step 1.
- Run seed, client seed and nonce through the verifier. The result must match your bet history.
If step 5 fails, the casino changed the seed after showing you its hash, and that is the one thing provably fair exists to catch.
Where provably fair applies
| Game | Provably fair? |
|---|---|
| In-house dice, crash, plinko, mines, limbo | yes, at casinos that build them |
| Aviator (Spribe) | seed system described by the studio |
| Crash X (Turbo Games) | rounds checkable by seed |
| Slots from outside studios | no, certified RNG |
| Live dealer tables | no, physical cards and wheels |
Our partner crypto casino takes Bitcoin deposits and pays out in coin.
Casinos with provably fair games
DuckDice
4.8/5Zentari Limitada
Provably fair originals in the lobby.
- Licence Anjouan ALSI-202509013-FI1
- 10 coins: BTC, ETH, LTC, SOL
- Provably fair games
- Sportsbook on the same account
Wolf.bet
4.8/5Cipher Games Ltd
Provably fair originals in the lobby.
- Licence Anjouan ALSI-132405048-FI3
- 13 coins: USDT, USDC, BTC, ETH
- Provably fair games
- Sportsbook on the same account
Shuffle
4.8/5Natural Nine B.V. · since 2023
Provably fair originals in the lobby.
- Licence Curaçao OGL/2024/1337/0628
- 20 coins: BTC, ETH, LTC, SOL
- Provably fair games
- Sportsbook on the same account
Metaspins
4.8/5Metaspins N.V.
Provably fair originals in the lobby.
- Licence Curaçao OGL/2024/1063/0437
- 8 coins: BTC, ETH, USDT, BCH
- Provably fair games
- Sportsbook on the same account
BitStarz
4.5/5Gareton B.V.
Provably fair originals in the lobby.
- Licence Curaçao OGL/2024/165/0185
- Provably fair games
Stake
4.3/5Medium Rare N.V.
Provably fair originals in the lobby.
- Licence Curaçao OGL/2024/1451/0918
- Provably fair games
- Sportsbook on the same account
BC.Game
4.2/5Operating company not stated · since 2017
Provably fair originals in the lobby.
- Licence Anjouan ALSI-202410011-FI1
- 150 coins: BTC, ETH, XRP, LTC
- Provably fair games
- Sportsbook on the same account
Casinos with provably fair originals first, then by score.
BC.Game and Stake also run provably fair originals; their reviews say what else we confirmed about them.
What provably fair does not prove
It does not prove the house edge is small, that withdrawals are paid, or that the casino is licensed. Those are separate questions, which is why our payout board checks licence, ID rules and caps alongside the games. Read the crypto dice and crash games pages for the games where it matters most.
Provably fair began with the first Bitcoin dice sites: see a short history of Bitcoin casinos. Terms such as seed and nonce are in the glossary.
Questions and answers
What does provably fair mean?
A system where the casino commits to a result before you bet by publishing a hash of a secret server seed. After the round, it reveals the seed and you can check the result was produced from it.
What is a server seed?
A random value chosen by the casino. Before you play, you see only its hash, a fingerprint that cannot be reversed. The seed itself is revealed later.
What is a client seed?
A value you control, which you can usually change in the game settings. It is mixed with the server seed so the casino cannot pick a result alone.
What is a nonce?
A counter that increases with every bet, so each round gets a different result from the same pair of seeds.
Does provably fair mean I will win more?
No. It proves the result was not changed after you bet. The house edge is still there.
Are slots provably fair?
Slots from outside studios use certified random number generators, not player-checkable seeds. Provably fair applies mainly to in-house games such as dice, crash, plinko and mines.
Which casinos on your board have provably fair games?
BitStarz, Wild.io, Shuffle, Metaspins, DuckDice, Wolf.bet, BC.Game and Stake run provably fair originals.
How do I verify a round?
Open the bet details, copy the revealed server seed, your client seed and the nonce, and run them through the casino's verifier or an independent one. The result should match.
Can a casino cheat with provably fair?
Not on a round you can verify, as long as the server seed hash was shown before the bet. That is why you should only rotate seeds when the casino shows a new hash first.
Is Aviator provably fair?
Spribe describes a seed system for Aviator, with the server seed hash shown before each round and player seeds mixed in.