Read this before you rely on a result
- It checks one bet, not a casino. A matching result shows that this bet followed from the seeds and the published method. It does not show that the casino is fair overall, that its games pay back what it says, that it holds a valid licence or that it pays out.
- It checks the published method. If a casino changes its method, our implementation may no longer match. The date we read each specification is in the table below.
- The hash check needs the hash from before the bet. Only the hash you saved before betting proves the seed was fixed in advance; a hash copied after the reveal proves nothing.
- Nothing leaves your browser. The calculation uses your browser’s built-in cryptography. The page makes no request when you press Verify and stores nothing.
- It is not a rating. We do not rate a casino through this tool; how we assess casinos is in our methodology.
Supported casinos and games
| Casino | Game | How the result is made | Casino’s specification | Checked against |
|---|---|---|---|---|
| Shuffle | Dice | Roll = floor(fraction × 10,001) ÷ 100, giving 0.00 to 100.00. | Provably Fair – Implementation (read 15 Oct 2026) Provably Fair – Game Events (read 15 Oct 2026) | Matches casino’s example Published example in the Dice section: clientSeed 'abc', serverSeed 'def', nonce 1 gives the fraction 0.43053962965495884 and the result 43.05. |
| Shuffle | Roulette | Pocket = floor(fraction × 37), giving 0 to 36 (single-zero wheel). | Provably Fair – Implementation (read 15 Oct 2026) Provably Fair – Game Events (read 15 Oct 2026) | Matches casino’s example Published example in the Roulette section: fraction 0.43053962965495884 (the same fraction the page gives for clientSeed 'abc', serverSeed 'def', nonce 1) gives pocket 15. |
| Shuffle | Keno | Ten fractions; value i = ceil(fraction × (40 − i)); each value is then moved past positions already taken, exactly as in the published loop, giving ten different numbers. | Provably Fair – Implementation (read 15 Oct 2026) Provably Fair – Game Events (read 15 Oct 2026) | Matches casino’s example Published example in the Keno section: clientSeed 'abc', serverSeed 'def', nonce 1 gives the values [18, 26, 7, 22, 31, 10, 23, 8, 24, 13] and the final numbers [18, 27, 7, 24, 35, 11, 28, 9, 31, 16]. |
| Wolfbet | Dice | Read the HMAC output as 64 hex characters; take the first five characters as a number; while it is 1,000,000 or more, take the next five; roll = (number mod 10,000) ÷ 100, giving 0.00 to 99.99. | Provably Fair – Implementation tab (read 15 Oct 2026) Official dice verifier – result for test input 1 (read 15 Oct 2026) Official dice verifier – result for test input 2 (read 15 Oct 2026) | Matches casino’s example Wolfbet's own verifier, typed input (no login): client seed 'abc', nonce 1, server seed 'def' shows 12.32 and the hashed server seed cb8379ac…5b34. Wolfbet's own verifier, typed input (no login): client seed 'my-own-seed-2026', nonce 0 and the 64-character server seed from our provably fair guide shows 18.6 (the first five characters, fcb8d, are above 999,999, so this also checks the skip rule). |
How each casino turns seeds into a result
Shuffle
HMAC-SHA256 with the server seed (as text) as key and "clientSeed:nonce:round" as message; the 32-byte output is read 4 bytes at a time, each group becoming a fraction byte1/256 + byte2/256² + byte3/256³ + byte4/256⁴; round 0, 1, 2 … supplies further bytes when more than 8 fractions are needed.
Server seed hash: SHA-256 of the server seed. Shuffle describes the seed as a 64-character hex string but does not say whether the text or the decoded bytes are hashed, so the tool checks both and says which one matches.
Not offered for Shuffle:
- Limbo. The published example gives a raw value of 2.298905 for the fraction 0.43053962965495884; the published formula gives 2.299439. The rounded result (2.29) agrees, but the intermediate figure does not, so we do not offer it.
- Mines. The published example ([20, 20, 4] → [20, 21, 4] for clientSeed 'abc', serverSeed 'def', nonce 1) does not follow from the published formula and seeds ([10, 15, 4] → [10, 16, 4]). Not offered.
- Plinko. The published example fractions (0.8320…, 0.8531 …) are not the fractions the published byte routine gives for the stated seeds (0.4305…, 0.6646 …). Not offered.
- Crash, Slide. Use a separate hash chain combined with a Bitcoin block hash; the published description does not give the formula from hash to multiplier. Not offered.
- Other games (Tower, Wheel, Blackjack, Hilo, Baccarat, Blitz, Chicken). Not included in this first version; we limited the tool to games whose full result can be shown in one step.
Wolfbet
HMAC-SHA256 as written in Wolfbet's published code, which calls CryptoJS.HmacSHA256 with the server seed as the first argument and "client seed_nonce" as the second. In CryptoJS the first argument is the message and the second the key, so the key is "clientSeed_nonce" (for example abc_1) and the message is the server seed. Wolfbet's own verifier gives the same results (see the vectors).
Server seed hash: SHA-256 of the server seed as text – Wolfbet's own verifier shows this value as “Server seed (hashed)” for the seeds we entered.
Not offered for Wolfbet:
- Other games. The implementation tab documents Dice only.
Casinos we profile that are not supported
These casinos name provably fair games, but we could not add them reliably. For the other casinos in our reviews that name provably fair games, we hold no record of a published method.
| Casino | Why not supported | Page we read |
|---|---|---|
| Roobet | Roobet's fairness page has a tab per game, but from our location a “Region Restricted” dialog covers the page and the tabs cannot be opened. We do not work around regional blocks. | Fairness page (15 Oct 2026) |
| Gamdom | Gamdom publishes sample code on CodeSandbox; the Dice code is behind a bot check we cannot pass, and for the other games we found no published example result to check our implementation against. Gamdom also uses a different input (one game hash from a hash chain instead of server seed, client seed and nonce). | Fairness page (15 Oct 2026) |
How to use it
- Before you play, set your own client seed and note the hashed server seed the casino shows.
- Play, then rotate the seed pair in the casino’s fairness settings. The casino reveals the previous server seed.
- Copy the revealed server seed, your client seed and the nonce of the bet you want to check into the form, pick the casino and game, and press Verify.
- Compare the result with your bet history, and check that the seed matches the hash you noted.
The background – what seeds, nonces and hashes are and what a check proves – is in provably fair: how to check a bet yourself. Casinos that name provably fair games are listed on provably fair crypto casinos.
Questions
What does this verifier check?
It recomputes the result of one bet from the server seed, client seed and nonce you enter, using the method the casino publishes for that game, and – if you enter it – checks that the server seed matches the hash you were shown before betting. It says nothing about whether the casino is fair overall, whether it is licensed or whether it pays out.
Why are so few casinos and games supported?
We only add a game when the casino publishes the exact method and our implementation reproduces the casino’s own published example or the result of its own verifier. Several casinos describe provably fair only in general terms, keep the method behind a regional block or publish examples that do not follow from their own formula; those are listed with the reason.
Are my seeds sent anywhere?
No. The calculation runs in your browser with its built-in cryptography functions. The page sends no request when you press Verify and stores nothing. Do not paste the server seed of a seed pair that is still active – it should only be revealed after you have rotated it.
My result does not match. Does that prove the casino cheated?
Not on its own. Check first that you chose the right casino and game, copied the seeds completely and used the nonce of that exact bet. Casinos can also change their method; the date we read each specification is shown in the table. If the values are exact and the result still differs, keep screenshots and contact the casino’s support.