Senior DeFi Smart Contract Architect - Remote

X-Team; United States; Remote; USD 180,000 - 240,000; Full time

Job summary

X-Team is seeking a senior protocol engineer to design, implement, and deploy secure on-chain infrastructure. You will own smart contract architecture from modeling to mainnet deployment, audits, and live monitoring.

This full-time, fully remote role requires hands-on experience with DeFi primitives, rigorous testing, and threat modeling to ensure upgradeable, cost-efficient, and resilient code in production.

Qualifications

• 4+ years of professional software engineering with at least 2+ years in production Solidity contracts.
• Expert-level Foundry (Forge, Cast) mastery including fuzzing and mainnet fork simulations.
• Deep understanding of EVM internals, gas optimization, Yul, and proxy/upgrade patterns.
• Practical knowledge of DeFi primitives (ERC-20/4626/721/1155, AMMs, oracles, liquidations).
• Comfort using AI coding tools to speed testing and documentation with sound judgment.
• Security-minded with awareness of reentrancy, oracles, front-running, etc.

Responsibilities

• Protocol Architecture: design and implement secure, gas-optimized Solidity contracts for lending, vaults, yield routing, liquidations, and access control.
• Testing & Simulation: write unit, integration, fork, fuzz, and invariant tests for zero-day resiliency.
• Security & Audits: prepare code for external audits and remediate findings.
• Cross-Functional Integration: collaborate with risk, frontend, indexer, and quantitative teams to build end-to-end dApps.

Skills

Solidity development

Smart contract security

EVM internals

DeFi primitives knowledge

Audits familiarity

Adversarial thinking

Tools

Foundry (Forge/Cast)

Mainnet fork simulations

Job description

X-Team is seeking a senior protocol engineer to design, implement, and deploy secure on-chain infrastructure. You will own smart contract architecture from modeling to mainnet deployment, audits, and live monitoring.

This full-time, fully remote role requires hands-on experience with DeFi primitives, rigorous testing, and threat modeling to ensure upgradeable, cost-efficient, and resilient code in production.