Quickstart

In the browser

Open the home page and press Verify in the "Check a chirp" section. It fetches a real round from the public relays and runs the whole check. Then open Fair draw.

From the command line

# the engine is plain JavaScript (Node 20+)
git clone <the Cricket repository>
cd cricket
node scripts/try-beacon.mjs

It prints the latest round, checks it and then tries a wrong round to show the refusal:

latest 33091322 roundAt(now) 33091322
ok true ms 50 randomness matches api true
wrong round ok? false

From your own code

import { verifyRound } from './src/engine/beacon.mjs';

const base = 'https://api.drand.sh/52db9ba70e0cc0f6eaf7803dd07447a1f5477735fd3f661792ba94600c84e971';
const r = await (await fetch(base + '/public/latest')).json();

const v = verifyRound(r.round, r.signature);
console.log(v.ok, v.randomness);   // true, 32-byte hex
console.log(v.steps);              // every step, for display

From a contract

import {CricketBeacon} from "./CricketBeacon.sol";

contract Dice {
    function roll(uint64 round, bytes calldata sig) external view returns (uint256) {
        bytes32 r = CricketBeacon.verify(round, sig);   // reverts if the signature is not the network's
        return uint256(r) % 6 + 1;                      // small modulo, fine for a die
    }
}