Haythem Sellami

Passionate about Smart Contract Engineering, Rust and all things Open Source. 6+ years of experience designing and deploying production-grade DeFi protocols. Worked on lending, AMMs, derivatives, and yield allocation protocols. Deep understanding of Solidity, EVM, and protocol security best practices.

Experience

Senior Smart Contract Engineer - Euler Labs (Nov 2023 - Apr 2025)

  • Designed and implemented Euler Earn, a capital allocation protocol that allows vault managers to deploy funds into any ERC-4626–compatible vaults.
  • Contributed to the test suite of Euler V2, a next-generation lending and borrowing protocol.
  • Contributed to EulerSwap, a novel AMM leveraging Euler V2's lending positions for enhanced capital efficiency. Focused on the factory and periphery contracts, and handled integrations with DEX aggregators including 0x, ParaSwap, and Tycho Protocol.
  • Conducted internal security audits and code reviews to ensure protocol robustness and maintain code quality.

Senior Smart Contract Engineer - Opyn (Apr 2020 - Nov 2023)

  • Wrote technical specifications and designed core components of options and derivatives protocols.
  • Built multiple robust smart contract systems from the ground up, including Gamma Protocol (first on-chain options protocol) and Squeeth (first power perpetual token).
  • Developed and deployed strategy vaults like Crab (delta-neutral on Squeeth) and ZenBull, integrated with Euler V1.
  • Built and maintained bot infrastructure for liquidations, oracles, and monitoring using Node.js, Python, OpenZeppelin Defender, and Google Cloud.
  • Integrated with AMMs, oracles, cross-chain messaging systems; deployed across multiple L2s.

Smart Contract Developer - Freelance (Jul 2018 - Mar 2020)

Projects & Contributions