Senior Solidity Engineer — Provably-Fair On-Chain Crash Game (BSC + Chainlink VRF)

About the project We run a crypto "crash" betting game (Mooning Monkey / MoonCrash) on BNB Smart Chain. The website, wallet integration, deposits/withdrawals, staking and NFT features are already built. Today the game's results and player balances run on a private off-chain server, and funds are custodial. What we're building We're upgrading the core game to be provably-fair and on-chain: player bets, randomness (crash point), and payouts handled by audited smart contracts, with an on-chain bankroll that guarantees winners can always be paid. You'll also help fix and re-deploy our existing token, staking, and NFT contracts to the live network. What you'll do - Design the smart-contract architecture for a provably-fair crash game (round lifecycle, randomness, settlement, bankroll/solvency). - Integrate Chainlink VRF for verifiable randomness. - Write production-grade Solidity with strong security (reentrancy protection, access control, pull-payments, pausability). - Deliver a full test suite (unit + fork + fuzz/invariant tests) and gas reports. - Fix our existing Web3 integration (ethers.js v6) and point contracts at the correct network. - Support a third-party security audit and remediate findings before mainnet launch. You're a great fit if you - Have shipped smart contracts that handle real user funds (DeFi / gambling / escrow). - Have integrated Chainlink VRF before and can explain the trade-offs. - Take security and testing seriously and have been through an external audit. ⚠️ Please note: This role includes a short, structured test task to verify your skills before we move forward. Applicants who are not willing to complete it should not apply.