Java Software Developer | Low Latency & FIX Connectivity | Financial Services | London, Hybrid
We’re partnered with a specialist engineering firm known for solving demanding performance challenges across financial markets and technology. Their teams design, build and optimise high-throughput, low-latency systems used by global financial institutions where speed, reliability and precision genuinely matter.
They’re now looking for a Java Software Developer with proven experience building high-performance JVM-based systems, ideally within trading, banking, fintech or front-office financial markets environments.
This role would suit someone with around 4–10 years’ commercial engineering experience who has worked on performance-critical Java systems and has exposure to FIX Protocol, connectivity, messaging or electronic trading flows.
It’s a hands-on engineering role for someone who enjoys solving hard technical problems, improving system performance and working close to real-time trading environments.
Location: London City, Hybrid working
⏱️Options: Contract-based, Inside IR35 (there is scope for a permanent option)
Level: Mid to Senior, ideally 4–10 years’ experience
What you’ll be doing:
- Designing, building and maintaining high-performance Java applications used in demanding real-time systems
- Working on low-latency, high-throughput platforms across financial markets and trading environments
- Supporting and enhancing connectivity across external venues, brokers, trading platforms or counterparties
- Working with FIX Protocol, FIX messages, tags, order flow, execution flow and connectivity issues
- Developing and improving testing, benchmarking and performance validation frameworks
- Identifying and removing bottlenecks through systematic performance analysis
- Working with JVM internals, including garbage collection, threading, concurrency, locking and memory optimisation
- Contributing ideas to improve architecture, speed, scalability and reliability
- Quantifying and documenting measurable performance improvements
- Working across both existing systems and greenfield development projects
- Communicating clearly with technical and non-technical stakeholders in client-facing environments
Requirements:
- 4–10 years’ commercial software engineering experience within Java-based development
- Proven experience building low-latency, high-throughput JVM-based systems
- Strong understanding of JVM internals, including GC, threading, concurrency, locking and performance tuning
- Experience with FIX Protocol, FIX connectivity, message flows, order routing or electronic trading connectivity
- Commercial experience working on performance-critical Java applications
- Exposure to trading, banking, fintech or wider financial markets environments
- Ability to troubleshoot performance issues and explain technical trade-offs clearly
- Comfortable working across existing platforms and new-build projects
- Strong attention to detail and a professional, precise engineering approach
Highly Desirable Experience:
- Front-office trading technology
- Market connectivity, broker connectivity, venue connectivity or exchange connectivity
- Messaging systems, event-driven architecture or real-time data flows
- Benchmarking, profiling and performance testing tools
- Consultancy, client-facing engineering or project-based delivery environments
- Linux, networking, distributed systems or high-performance computing concepts
If you are interested in this Java Software Developer Role, please apply directly to this advert with your updated CV.