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Check any Stake-Originals result against its seed pair - Mines, Plinko, Dice, Limbo, Keno and Crash, across 9 provably-fair casinos. Everything runs in your browser; your seeds never leave your device.
Choose any game above to open its dedicated verifier - paste your server seed, client seed and nonce to recompute the exact result.
Provably fair verification lets anyone independently recompute a game's result from its server seed, client seed and nonce - confirming the casino could not have altered the outcome after the bet. Browse all casinos & games
Every casino below runs the same Stake-style HMAC-SHA256 engine - one verifier covers them all. Tap any casino to open its dedicated checker.
Provably fair is a cryptographic system that lets you prove, for yourself, that a casino did not rig the outcome of a bet. Instead of trusting that the house is honest, you get mathematical evidence. The casino commits to a secret before you play, you add your own randomness, and after the fact anyone can recompute the exact result and confirm nothing was changed. It is the core feature that separates crypto Originals like Dice, Mines and Crash from a traditional black-box casino.
This page explains how the system works, how to verify any result yourself, which casinos and games it covers, and why no predictor can ever beat it. The verifier above re-derives outcomes for the Stake-engine Originals across every provably fair casino Spindex tracks.
Every provably fair result comes from one deterministic formula fed three inputs. Change any input and the result changes; keep them the same and the result is identical every time, which is exactly what makes it verifiable.
A long random string the casino generates and keeps secret. Before you bet, it shows you only the SHA-256 hash of that seed, a fingerprint that commits the casino to a value it cannot change later without breaking the hash. This commitment is the heart of the whole system.
A string you control, and can change at any time. Because you contribute randomness the casino did not choose, it cannot pre-compute favorable outcomes for a known server seed. Setting your own client seed is what makes the guarantee yours, not just the casino's.
A counter that increases by one with every bet on the same seed pair, so each wager produces a unique result even though the seeds stay the same. Server seed, client seed and nonce together identify exactly one outcome.
The algorithm that ties it together. The casino computes HMAC-SHA256 of your client seed, nonce and round against the server seed, then converts that hash into the game result through the game's own rules. It is a one-way function: trivial to verify after the server seed is revealed, impossible to reverse beforehand.
Because the server seed was committed in advance, the casino cannot alter it after seeing your bet. When you rotate seeds, it reveals the original unhashed server seed. Feed that plus your client seed and nonce into a verifier, and the same algorithm reproduces the same outcome, which is your proof the round was fair.
Verifying a result takes about a minute and needs no coding. In your casino, rotate or refresh your seed pair so it reveals the unhashed server seed you were playing on. Copy that server seed, your client seed and the nonce of the bet you want to check. Paste all three into the verifier at the top of this page, choose the game, and it re-derives the outcome. If the tool's result matches what you saw in the game, the round was provably fair and was not touched after you placed it.
You can check any Stake Original this way. Jump straight to a dedicated checker for Stake Dice, Mines, Plinko, Crash, or Limbo.
Yes, and it is worth being precise about what it does and does not guarantee. Provably fair is real cryptographic proof that a specific result was generated from committed inputs and not tampered with after your bet. It genuinely stops a casino from changing an outcome once it sees your wager.
What it does not do is remove the house edge. A game can be flawlessly provably fair and still be designed to return the casino a profit over millions of bets. Verification is about honesty, not about improving your odds. And the checker itself is safe to use: the tool on this page hashes everything locally in your browser, so your seeds never leave your device.
This is the most searched question and the answer is a firm no. The server seed stays hidden until you decide to rotate it, so there is no information available that could reveal a future result. No formula, script, hack, or predictor can forecast the next Dice roll, Mines tile or Crash multiplier, because the data needed to compute it does not exist yet.
Anything sold as a provably fair predictor, a crash formula, or an RNG cracker is a scam, usually a front for an affiliate trap or malware. The whole point of the system is that results are verifiable only after the fact. Use verification for what it is good for, confirming past rounds were honest, and treat every prediction claim as a red flag.
Provably fair applies to a casino's in-house Originals, where the studio controls the math. Here are the most popular, all verifiable with the tool above.
The simplest to verify: the hash converts to a single number that maps directly to the roll or the crash multiplier. Open the Dice checker or the Limbo checker to test a result against your seed pair in seconds.
The crash point is derived from the same HMAC-SHA256 output, adjusted for the house edge, then mapped to a bust multiplier. Every past round is verifiable on the Crash checker, but no round is predictable.
Here the hash seeds a shuffle or a path: which tiles hide mines, or which slot a Plinko ball lands in. Re-run the same seeds through the Mines verifier or Plinko verifier to confirm the board you were dealt.
Because they share the Stake engine, the same verification works across Stake, Rainbet, Roobet, BC.Game, Gamdom, Shuffle and Duel. Each casino above has its own dedicated checker, and the grid earlier on this page links every one.
Provably fair is one of the strongest reasons players prefer crypto casinos over traditional online casinos, alongside instant payouts and open odds. If you are choosing where to play, compare current welcome offers on our casino bonuses page, or read the full Stake and Rainbet guides. Keep in mind that most provably fair guarantees cover a casino's Originals, not third-party slots, which rely on the providers' own certified RNGs.
A traditional online casino asks you to trust a licensed but private random number generator: you cannot see it, and you cannot check any individual result. Provably fair flips that. The math is public, the server seed is committed before you bet, and every outcome is independently verifiable after the fact. You are no longer trusting a promise; you are checking a receipt. It does not change the house edge, but it removes the question of whether the casino is being straight with you.
Provably fair is a cryptographic system that lets you confirm a casino did not manipulate the outcome of a bet. Before you play, the casino commits to a secret server seed by showing you its hash. You add your own client seed, and each bet uses an increasing nonce. Once you rotate seeds, the casino reveals the original server seed, and anyone can recompute the exact result. If it matches, the game was fair.
Every result is produced by HMAC-SHA256 using three inputs: the server seed (committed in advance and hashed), your client seed, and the bet's nonce. Because the server seed is locked in before you bet, the casino cannot change it after seeing your wager. When you rotate seeds it reveals the unhashed server seed, and feeding the same inputs into the same algorithm reproduces the same outcome every time.
Rotate your seed pair in the casino so it reveals the unhashed server seed, then paste that server seed, your client seed and the bet's nonce into a verifier like the one on this page. The tool re-derives the outcome and shows whether it matches what you saw in-game. A match proves the round was not altered after you bet.
Yes. It is genuine cryptographic proof, not marketing. What it proves is that a specific result was generated fairly from committed inputs and not tampered with. What it does not remove is the house edge: a game can be perfectly provably fair and still be built to profit the casino over time, so verification is about honesty, not about tilting the odds in your favor.
No. The server seed stays hidden until you choose to rotate it, so no tool, formula, script or predictor can know a future result in advance. Anything advertising a provably fair predictor, hack, or crash formula is a scam. Verification only confirms that past results were fair; it cannot forecast the next one.
On Stake-engine games, the crash point is derived from the same HMAC-SHA256 output as every other Original. The hash is converted to a number, a small house-edge adjustment is applied, and that maps to the multiplier at which the round busts. Because it comes from the committed seed pair, you can verify any past crash round, but you cannot predict the next one.
Stake, Stake.us, Rainbet, Roobet, BC.Game, Gamdom, Shuffle, Duel and other Stake-engine sites all run the identical HMAC-SHA256 model, so one verifier covers them all. Note that provably fair usually applies to a casino's in-house Originals (Dice, Mines, Crash and so on), not to third-party slots, which use the providers' own certified RNGs.
Yes. The verifier on this page runs entirely in your browser using the Web Crypto API. Your server seed, client seed and results are never sent to Spindex or any server, so nothing sensitive leaves your device.
Provably fair proves a game is honest; it does not make it winnable. Every Original carries a house edge, and verifying results will not change your long-run odds. Treat these games as entertainment, never as income, set limits before you start, and if gambling stops being fun, visit our responsible gambling page for support resources.
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