Verify any CS2 gambling roll, in your browser.

Every provably-fair round uses three secrets. The server seed is generated by the site. Before the round starts, the site publishes a SHA-256 hash of it, the seed's commitment. Once the round ends, the site reveals the original server seed so the gambler can hash it and confirm the site didn't swap it mid-round.

The second secret is the client seed, the gambler provides it, so the site can't game it. The third is the nonce, a round counter that increments per roll so the same seed pair produces fresh outcomes.

To produce the outcome, the site runs HMAC(serverSeed, `clientSeed-nonce`) using SHA-256 (or SHA-512 on some stacks). The HMAC output is a fixed-length hex string. The site takes the first 8 hex characters as a 32-bit unsigned integer and decodes it into a game outcome, e.g. uint32 % 15 for a CSGOEmpire-style roulette.

Everything this tool does is run the same HMAC + decoders yourself, in your own browser's SubtleCrypto, over seeds you supply. If our result matches the site's declared outcome, the round was fair under the stated algorithm. If it doesn't, either the message format / hash algorithm differs from our defaults, or the site is running a different algorithm than it publishes.

Want a deeper walkthrough with a worked example? Read our long-form provably-fair guide.