Smart Contract Engineer

As a Smart Contract Engineer at X-Team, you will take deep ownership of smart contract architecture for a secure on-chain infrastructure powering the next generation of open finance. In this role, you design, implement, and battle-test critical smart contracts that manage significant TVL and capital-efficient primitives. This is a full-time, fully remote engagement open to LATAM, USA, and Canada, with meaningful overlap with US/EU working hours.

What you'll do

• Design and implement secure, gas-optimized Solidity smart contracts for lending, borrowing, vaults, yield routing, liquidations, and access control (approximately 40% of your time)
• Write extensive unit, integration, fork, fuzz, and invariant tests utilizing modern frameworks to ensure zero-day resiliency (approximately 30% of your time)
• Prepare codebases for top-tier external audits, remediate findings, and design proactive on-chain risk mitigation and monitoring strategies (approximately 15% of your time)
• Collaborate closely with risk, frontend, indexer, and quantitative engineering teams to build seamless, secure end-to-end dApps (approximately 15% of your time)

What you bring

• 4+ years of professional software engineering experience, with at least 2+ years writing, deploying, and maintaining highly secure Solidity smart contracts in production
• Expert-level mastery of Foundry (Forge, Cast) including advanced fuzzing, invariant testing, and mainnet fork simulations
• Thorough understanding of EVM internals, storage layouts, gas optimization strategies, assembly (Yul), and standard proxy and upgradeability patterns
• Practical, working knowledge of core financial primitives such as ERC-20, ERC-4626, ERC-721, ERC-1155, AMMs, lending pools, oracles, and liquidation engines
• Comfort using modern AI coding tools (e.g., Cursor, Claude, Copilot) to accelerate unit testing, documentation, and boilerplate development, backed by the critical judgment required never to trust raw model outputs blindly
• An obsessive awareness of common attack vectors including reentrancy, oracle manipulation, front-running, rounding errors, and access-control flaws

Nice to have

• Prior experience guiding a protocol through a major external audit (e.g., Trail of Bits, OpenZeppelin, Spearbit) or participating in competitive security audits
• Exposure to Rust-based smart contract environments (SVM/Solana, CosmWasm) or zero-knowledge (ZK) rollup architectures
• Familiarity with off-chain automation infrastructure like Keepers, Defender, or Gelato