Senior Backend Engineer, Web3

🏷️Title: Senior Backend Engineer, Web3

👫Department: Engineering

📍Location: UK or Europe, Remote

About Block Labs

Block Labs is a leading force in the Web3 space, incubating, investing in, and accelerating top-tier fintech, crypto and iGaming projects. With a mission to shape the future of decentralized technology, we partner with visionary startups to raise funding, refine product-market fit, and grow their audiences. Our diverse team drives innovation, using deep industry expertise and an extensive network to empower the next wave of blockchain-driven companies. At Block Labs, we’re passionate about turning bold ideas into breakthrough success.

About The Role

As a Senior Backend Engineer, you will be responsible for designing and building scalable, high-performance backend services for blockchain-integrated applications. You will work closely with engineering and product teams to develop APIs and infrastructure that power Web3 experiences, ensuring security, reliability, and efficiency.

Key Responsibilities:

• Develop and maintain backend services using NestJS (Node.js, TypeScript).

• Design and implement secure, scalable APIs for Web3 applications, integrating with wallets, blockchain nodes, and smart contracts.

• Work with ethers.js, web3.js, or viem to interact with blockchain networks (Ethereum, Polygon, Solana, etc.).

• Implement authentication mechanisms.

• Optimize database queries and caching strategies for high-throughput systems.

• Collaborate with frontend and blockchain teams to ensure seamless integration of Web3 functionalities.

• Build and maintain event-driven architectures for transaction processing.

• Implement security best practices, including encryption, access control, and smart contract interactions.

• Write clean, maintainable, and testable code while contributing to technical documentation.

• Support the evolution of API standards and developer experience in the Web3 space.

About You:

• 4+ years of backend development experience with Node.js and TypeScript.

• 2+ years working with NestJS or similar frameworks.

• Experience designing and maintaining APIs optimized for mobile applications.

• Strong understanding of blockchain fundamentals and experience integrating with EVM-compatible chains.

• Strong understanding of account abstraction and smart contract wallets (e.g., Safe, EIP-4337).

• Experience with DevOps tools and cloud providers (AWS/GCP/Azure, Docker, Kubernetes).

• Knowledge of authentication best practices and Web3 identity solutions.

• Strong problem-solving skills and ability to work autonomously in a remote-first environment.