Provably Fair Verifier — Free SHA-256 Game Result Checker
Verify dice, crash, mines, plinko, and limbo results from any provably fair crypto casino. Runs in your browser. No sign-up, no data sent anywhere.
How to Use This Verifier
Open the fairness tab in your casino
Most provably fair casinos have a "Fairness", "Provably Fair", or "Seeds" tab in the game interface or your account settings. Navigate there to find your seed data.
Rotate your seed pair to reveal the server seed
Click "Rotate" or "Change Seeds" to end the current seed pair. The casino will then reveal the previous (unhashed) server seed. This is the value you need.
Copy the three values into this tool
Paste the revealed server seed, your client seed, and the nonce for the specific round you want to verify. Optionally paste the hashed server seed to check the commitment.
Compare the output to what you saw in-game
The verifier will compute the result using the same HMAC-SHA256 algorithm. If the number matches what the casino showed you, the round was fair. If it does not, see our troubleshooting section below.
For a more detailed walkthrough with screenshots, see our full step-by-step verification guide.
Why Verify Independently?
A casino's own verifier runs through the casino's infrastructure -- their servers, their code, their interface. Even if the math is correct, you are trusting that the tool itself has not been modified. An independent check eliminates that trust requirement entirely.
This verifier runs the exact same HMAC-SHA256 calculation using your browser's built-in Web Crypto API. If this tool and the casino's tool both produce the same number from the same inputs, the round was provably fair -- verified by two completely separate pieces of infrastructure. That is the entire point of provably fair gaming: removing the need to trust a single party.
Casinos Supported by This Verifier
| Casino | Supported Games | Algorithm |
|---|---|---|
| Stake | Dice, Crash, Mines, Plinko, Limbo, Hi-Lo | HMAC-SHA256 (standard) |
| BC.Game | Dice, Crash, Mines, Limbo | HMAC-SHA256 (variant) |
| Roobet | Crash, Dice, Mines | HMAC-SHA256 (standard) |
| Shuffle | Dice, Crash, Limbo | HMAC-SHA256 (standard) |
| Bustabit | Crash | HMAC-SHA256 (custom crash) |
| Duelbits | Dice, Crash, Mines, Plinko | HMAC-SHA256 (standard) |
Looking for a provably fair casino to play at?
See our ranked list of 12 verified provably fair casinos -- every operator tested with real money.
Important Caveats
Aviator (Spribe)
Aviator by Spribe uses SHA-512, not SHA-256, and derives the client seed from the first 3 bettors in each round. This tool does NOT support Aviator. Use Spribe's official verifier instead.
BC.Game Variant
BC.Game has used non-standard formula variants in the past. Results may differ slightly from this tool. Always verify against their published documentation for the specific game version.
Bustabit Instant-Crash Quirk
Approximately 1 in 101 rounds on Bustabit-style crash games crashes at 1.00x by design. This is the house edge mechanism, not a bug. For a deep dive, see our crash algorithm documentation.
Verification Doesn't Match?
The most common causes: (1) trailing whitespace in a seed field -- always trim before pasting, (2) using the hashed server seed instead of the revealed (unhashed) one, (3) wrong nonce -- each round has a unique nonce starting from 0, and (4) the casino uses a non-standard algorithm variant not covered by the default presets.
This verifier covers the most common provably fair implementations used by major crypto casinos. If your casino uses a proprietary algorithm not listed above, select "Custom SHA-256" to compute the raw HMAC output and compare it manually against the casino's documentation. For the best provably fair operators, see our best provably fair casinos list.
Frequently Asked Questions
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