Provably fair, explained
Before you place a single bet, loopstr shows you the SHA-256 hash of a secret server seed. Every round's outcome is HMAC-SHA256(serverSeed, clientSeed + ":" + nonce), where the client seed is yours to change and the nonce counts your rounds (0, 1, 2, ...). When you rotate seeds, the old server seed is revealed. If its hash matches what was published, the house could not have changed a single outcome after the fact. You can check every round below, entirely in your browser.
Verify a round
Fill in the fields from your round history and hit Verify.
Check a seed hash
Paste a revealed server seed to recompute its SHA-256 and compare with the hash you were shown before betting.