Paste the server seed (revealed after the bet), your client seed and the nonce. The outcome is recomputed locally in your browser — if it matches what the casino showed you, the bet was fair. Nothing is sent anywhere.
Before your bet, the casino shows a hash of its server seed — a commitment it cannot change later. Your client seed and a per-bet nonce are mixed in via HMAC-SHA256(serverSeed, clientSeed:nonce), and the digest is converted to floats in [0, 1). Each game maps those floats to an outcome: dice multiplies by 10001, coinflip splits at 0.5, mines and keno run Fisher–Yates shuffles, plinko turns each float into a left/right bounce, roulette multiplies by the tile count, and crash/limbo share the 2⁵² instant-bust formula.
What this proves: the result was fixed before you bet and the casino didn't change it after seeing your stake. What it doesn't prove: that the site will pay you out. Fairness of outcomes and solvency are different risks — check payout records in our site rankings before depositing.
Implementations differ slightly between operators. If a result mismatches, check the casino's own verifier page first — some use clientSeed:nonce:round or a different float width.
Free tool by SkinsPoint.com — 18+, play responsibly.