Verify a round

The same math the house runs, in your browser. Outcome hash = HMAC-SHA256(server seed, client seed:nonce); every draw a game needs comes from sha256(hash || i).

How provably fair works here

Before you play, the house picks a secret server seed and shows you only its SHA-256 hash: the commitment. It cannot change the seed later without the hash changing.
You hold a client seed you can set, and every round counts a nonce up by one. The round's outcome hash is HMAC-SHA256 of the server seed over "client seed:nonce", so neither side can pick an outcome alone.
Each game turns that hash into its result by fixed, published rules (the Provably fair line on every game page); when a game needs more than one draw, draw i is sha256(hash || i).
When you rotate, the old server seed is revealed. Hash it here: it must match the commitment you saw, and every round under it must recompute to what the server settled.

Server seed (revealed)

Client seedNonce

GameParameters (JSON: the round's params, plus the moves of a live game)

Result

Fill the seeds and press Recompute, or load one of your rounds.

My last 20 rounds

Every settled round under a revealed seed, recomputed here and held against what the server paid.