'Provably fair' gets thrown around so much it's started to sound like marketing. It isn't — it's a specific cryptographic protocol that lets you, the player, verify every roll was decided before you played. Here's how.

The three ingredients

Server seed — a random secret the site generates and commits to before you play.
Client seed — a value you choose (or the default one the site assigns).
Nonce — a counter that increments with each roll.

The commitment step

Before you start rolling, the site publishes a hash of the server seed (e.g. SHA-256). The site can't change the server seed after this — any change would produce a different hash. You have a cryptographic guarantee that the secret is locked in.

The roll itself

For each roll, the site computes HMAC-SHA256(server_seed, client_seed + nonce)and maps the result onto the dice outcome. Same inputs always produce the same outcome.

The reveal step

When a session ends (or you rotate seeds), the site reveals the server seed. You hash it and confirm it matches the earlier commitment. Then you recompute every roll yourself — if any result doesn't match, the site cheated.

What provably fair does NOT guarantee

That the house edge is small.
That the site will pay you out.
That your bankroll is safe.

Provably fair only certifies that the random number wasn't tampered with. Trust the math, verify the operator separately.

Verifying a Rollit roll

Go to your account → roll history. Each round shows the server seed hash, your client seed, the nonce, and the revealed server seed. Any open-source provably-fair verifier (or a few lines of JS) will confirm the result.

Provably fair dice, explained