Provably Fair Verifier
Paste the values from a site's fairness panel and this tool re-runs the cryptography: it checks that SHA-256(server seed) matches the hash the site published before you bet, then derives HMAC-SHA256(server seed, client seed:nonce) and the common game outcomes. Everything runs locally in your browser via WebCrypto, no value you enter is sent anywhere.
What this proves, and what it doesn't
A matching commitment proves the site didn't swap its seed after seeing your bets; matching outcomes prove each roll followed deterministically from the seeds. Two limits to keep in mind. First, the HMAC step is near-universal, but the mapping from digest to game result varies by site, compare against the formula on the site's fairness page, and treat the derivations here (roulette % 15, percent % 10001 / 100, bustabit-style crash) as the common defaults. Second, a fair roll says nothing about the odds being good: a case with a 30% house edge can be perfectly provably fair. Full walkthrough in our provably fair guide.
Every casino in our directory has its licence checked on the regulator’s own register, and is re-checked monthly.