Provably fair, explained
"Provably fair" is one of the few things at a crypto casino you can verify mathematically. Here's how it works — and what it doesn't cover.
How provably fair works
Before a bet, the casino commits to a secret server seed by publishing its hash. You contribute a client seed. The outcome is computed from both seeds, so neither side can change the result after the fact. Afterwards the casino reveals the server seed, and you can hash it to confirm it matches the earlier commitment — proving the game wasn't rigged against you.
What it protects against
It protects against the operator manipulating individual game outcomes — the classic "is the dice loaded?" worry. For provably-fair games (dice, crash, plinko and similar), you can independently verify every result. That's a genuine, meaningful guarantee that most traditional online casinos can't offer.
Verifying a result, step by step
The check is concrete enough to do by hand. Before betting, note the published hash of the server seed (a fingerprint that can't be reversed). Place your bet with your client seed and a nonce (a counter). After, the casino reveals the actual server seed; you hash that revealed seed yourself and confirm it equals the fingerprint shown earlier — if it matches, the seed existed before your bet and couldn't have been chosen to make you lose. Then you re-run the casino's published formula (server seed + client seed + nonce) and confirm it produces the exact outcome you got. Most provably-fair sites ship a one-click verifier and let you rotate your client seed so you control half the input.
Provably fair vs RNG slots
An important boundary: provably fair typically covers a casino's in-house originals (dice, crash, plinko, mines). Third-party studio slots (Pragmatic, Hacksaw, etc.) run on the provider's certified RNG, not the casino's seed scheme, so you usually can't run the same seed-hash check on them. That doesn't mean slots are rigged — reputable providers are independently audited (eCOGRA, iTech Labs) — but the trust model is different: provably-fair is "verify it yourself", audited-RNG is "trust an independent lab". Know which one a game uses before assuming you can verify it.
What it does NOT protect against
Provably fair says nothing about whether the casino will pay your winnings. It doesn't prove solvency, doesn't stop withdrawal freezes, and doesn't apply to third-party slots (which use the provider's RNG, not the casino's). The house edge is still built into the math. So fairness ≠ safety — pair it with proof of reserves and trust signals.
FAQ
No. It proves individual game outcomes were not manipulated, but says nothing about solvency or whether you can withdraw. Combine it with on-chain reserves and trust ratings to judge safety.
Yes — that is the point. After a bet the casino reveals the server seed; you hash it and confirm it matches the commitment published before the bet, then re-run the formula to reproduce your outcome. Most provably-fair casinos provide a one-click verifier tool.
Usually not in the same way. Provably fair typically covers a casino's in-house originals (dice, crash, plinko). Third-party studio slots run on the provider's certified RNG audited by independent labs, so you trust the audit rather than verify a seed hash yourself.
Methodology & disclaimer. Figures are derived from on-chain transfers attributed to wallets we associate with each operator, plus third-party ratings shown with their source. Blockchain attribution carries inherent uncertainty, and reserves are an all-chain best-effort estimate from mapped wallets — coverage varies by operator. These pages describe observed activity and third-party data only; they are not an endorsement of any operator and not a statement on any operator's solvency, legality, fairness, or safety, and nothing here is financial, legal or investment advice. See how we attribute on-chain activity · about us · report a correction. Data updates roughly every 30 minutes. 18+ only. Gambling can be addictive — see responsible gambling resources.