Job Description

? Senior Blockchain Engineer - DeFi / Smart Contracts
? Lausanne, Switzerland (Hybrid) | ? 80-100% | ? Permanent contract
A fast-growing Swiss technology company is looking for an experienced Senior Blockchain Engineer to strengthen its DeFi product team. In this role, you'll be at the heart of designing and building innovative decentralized finance solutions, working in a collaborative environment where new ideas are encouraged and quickly turned into reality.
? Your Mission

• Take ownership of the design, development, testing and deployment of smart contracts within a sophisticated DeFi ecosystem.
• Translate business and product requirements into secure, scalable blockchain architectures.
• Work hand-in-hand with fellow engineers, product owners and other stakeholders to deliver new blockchain functionalities.
• Apply rigorous testing methodologies (unit, integration, fuzzing) to ensure robustness and security.
• Help evolve the blockchain infrastructure, improve internal tools, and streamline development workflows.
• Keep a close eye on emerging DeFi trends, L2 solutions and smart contract best practices to push innovation forward.

? What You Bring

• A deep interest in DeFi innovation and blockchain technologies, coupled with strong analytical and problem-solving skills.
• The ability to thrive in a fast-moving environment, make informed decisions with partial information, and work autonomously while collaborating effectively.
• Several years of hands-on blockchain development, including:
• Advanced proficiency in Solidity and smart contract security.
• Solid understanding of DeFi primitives, DEXs, and liquidity mechanisms.
• Strong generalist software engineering background (multiple languages, testing, clean architecture).
• Experience working in multidisciplinary engineering teams on complex, scalable codebases. Leadership experience is a plus.
• Excellent communication skills in English; proficiency in French is a strong asset.

? Our Technical Environment

• Blockchain: EVM-compatible chains, Solidity, Foundry/Hardhat toolchains, extensive smart contract test coverage including fuzzing and property-based testing.
• Frontend: Modern TypeScript stack with React-based frameworks, tightly integrated with blockchain backends.
• Backend & Infrastructure: Node.js, REST/GraphQL APIs, Dockerized services, CI/CD pipelines for rapid iteration and secure deployments.
• Architecture: Modular on-chain/off-chain integration, data indexing, monitoring and analytics dashboards to ensure reliability and performance.
• Culture: Developer-driven workflows, open discussions on architecture choices, strong emphasis on code quality, security, and peer review.

? Why Join

• Collaborate with a high-caliber team of blockchain specialists to build cutting-edge DeFi products.
• Benefit from a competitive compensation package aligned with your expertise.
• Enjoy a hybrid working model, with two remote days per week and flexible hours.
• Contribute to impactful projects at the forefront of the DeFi ecosystem.

Skills Required