Senior Backend Engineer - Cross-Chain Solver

LI.FI is simplifying multi-chain DeFi for traditional financial institutions, fintechs and service providers by offering a unified API to access all on-chain liquidity across major blockchains for best price same-chain and cross-chain swaps. We are a passionate team on a mission to enable a fairer, more decentralised world. Apart from the tech, we care a lot about user experience and aim to make complex technologies accessible to everyone.

We're looking for a Senior Backend Engineer (Cross-Chain Solver) to lead the development and optimization of our cross-chain solver. This is a critical role that will directly impact our ability to execute fast, reliable, and cost-effective cross-chain transactions for our users. You'll be building core infrastructure that enables seamless movement of assets across different blockchain networks and helping solve one of the biggest challenges in crypto: cross-chain interoperability. The ideal candidate has a strong backend engineering background, proficiency in TypeScript (ideally with NestJS), and experience with statistical analysis and data structures/algorithms. This position reports to our Technical Lead.

Please note: This is a fully remote role, but we have a strong preference for candidates based in the EMEA region or those who can reliably overlap with EMEA working hours for better collaboration.

• 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 throughout 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.

• At least 5 years of backend development experience.

• Strong proficiency in TypeScript/NestJS.

• 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.

• 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.).

• Engineers looking to transition from backend to smart contract engineering.

• People focused on MEV.

• Full-stack engineers still doing UX or frontend development.

• Individuals who thrive in top-down management structures with rigid task assignments.

We encourage you to apply if you feel your experience and skills equip you for this job but are not listed here!

• Embracing the differences

  • Embrace your own differences

  • Respect and welcome the unique qualities of others

  • See others’ differences as an opportunity to grow

• Own it, do it

  • Own tasks end-to-end

  • Hold yourself to a high bar for execution

  • Make bold decisions, and be accountable

  • Understand your limitations and seek for help

• Fail forward

  • Try - don’t be afraid to fail

  • Learn - don’t make the same mistake twice

  • Adapt - grow with the experience

• Have fun together

  • Take the time to get to know and understand each other better

  • Don’t take yourself too seriously and keep it light-hearted

  • Fun should be coming from a place of love and respect

• Annual team offsites (Thailand in 2023 and Vietnam in 2024 were a blast, Marrakech in March 2025 was blast-ier; let’s see what happens in 2026!)

• 30 days of PTO

• Flexible remote days

• Flexible working hours

• Equity participation from day 1

• Entitlement to work computer (choice of equipment)

• 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.

If you join us as an independent contractor, you’re only entitled to the first five benefits of this list.

Setting yourself up for success starts with the application! Click here to discover valuable tips that will help you navigate our application process effectively.

LI.FI is an equal opportunity employer. We encourage individuals of all backgrounds to apply. Join us in our dedication to fostering a workplace that values and respects each team member's unique contributions.

Shortlisted candidates will undergo a comprehensive interview process, including a people operations interview, a take-home assignment, a meet-the-team & founder interview, and a reference check.

For more information, visit our page detailing our hiring process!