Senior Backend Engineer

Summary

Join LI.FI as a Senior Backend Engineer (Cross-Chain Solver) and lead the development and optimization of our cross-chain solver, a critical role directly impacting our ability to execute fast, reliable, and cost-effective cross-chain transactions. You will build core infrastructure enabling seamless asset movement across blockchain networks, solving a major challenge in crypto: cross-chain interoperability. The ideal candidate possesses a strong backend engineering background, proficiency in TypeScript (ideally with Nest.js), and experience with statistical analysis and data structures/algorithms. This fully remote position, with a preference for EMEA-based candidates, reports to our Technical Lead. LI.FI offers a variety of benefits including flexible remote work, flexible hours, equity participation, and a generous personal development budget.

Requirements

• At least 5 years of backend development experience
• Strong proficiency in TypeScript/Next.js
• Experience with statistical analysis or data science and/or strong background in data structures and algorithms
• Deep understanding of blockchain architecture, particularly around transaction execution and mempool dynamics
• Experience with building high-throughput services
• Familiarity with different blockchain RPC interfaces and their quirks
• Strong background in data structures and algorithms
• Experience with monitoring and observability tools
• Familiarity with caching solutions (ie. Redis)
• Strong system design skills, with the ability to think like an architect
• Ability to work autonomously in a fast-moving, flexible environment
• Problem-solving mindset with a focus on delivering practical, scalable solutions
• Strong communication skills, ability to give and receive feedback effectively
• Ownership mindset, curiosity, and willingness to navigate ambiguity

Responsibilities

• Design and implement a high-performance cross-chain solver that monitors and executes transactions across multiple blockchain networks
• Develop pricing and routing algorithms to optimize transaction throughput and capital efficiency
• Implement scalable, efficient liquidity management and rebalancing strategies across multiple chains
• Build robust monitoring and alerting systems to ensure solver reliability
• Optimize transaction execution logic, ensuring a competitive balance between bid frequency and win rate
• Design robust transaction submission and management systems
• Implement comprehensive testing frameworks to ensure system reliability and security
• Collaborate with smart contract developers to integrate with on-chain protocols
• Maintain high coding standards, conduct code reviews, and ensure best practices for performance, maintainability, and security

Preferred Qualifications

• Proficiency in Rust
• Experience building a solver in a similar environment
• Experience with cross-chain bridges or DEXs
• Background in trading systems or market making
• Exposure to different blockchain VMs (EVM, SVM, Move, etc.)

Benefits

• Annual team offsites
• Flexible remote days
• Flexible working hours
• Equity participation from day 1
• Entitlement to work computer (choice of equipment)
• 1 Conference per year near your city of residence
• An annual 1,000€ personal development budget once you have worked 6+ months (pro-rated the first year)
• A one-time 1,000€ remote budget to use on coworking, office setup, etc
• Unlimited PTO