The learning library
Fairness & verification
Put it into practice
Choose a verifier Check a recorded result
Choose the operator and algorithm behind a recorded bet, then replay it in your browser.
FAQ
Does a matching replay prove the casino is fair?
No. It shows the inputs you supplied reproduce the result under that algorithm. A full server seed hash saved before your first bet adds evidence against later seed substitution, subject to the authenticity and timing of the record. It does not establish that the seed was chosen before an unpredictable client seed unless that order was recorded. It says nothing about withdrawals or licensing, and does not by itself check payouts.
I didn't save the hash before playing. Is my check worthless?
Not worthless, just weaker. A match still shows the result is consistent with the revealed inputs. For your next session, save the full hash first, with its seed-pair context and a record of timing, so the check can show more.
A provably fair check answers one narrow question: do these inputs produce this result? Whether that adds up to evidence of a fair bet depends on what you recorded, and when. These guides walk through the evidence step by step, from the commitment you save before the first bet to what to do when a replay doesn't match.
