Role: Java Low Latency Engineer / Java Performance Engineer Location: London / Hybrid - 3 days in London office Day rate: DoE Sector: Wealth Management, Investment Banking, Asset Management, Personal & Corporate Banking We are seeking an experienced Java Low Latency Engineer / Java Performance Engineer to join a high-performing engineering team responsible for building and optimising mission-critical, event-driven systems operating in ultra-low latency environments. You will work on the design, development, and optimisation of high-throughput, high-frequency systems where performance, scalability, and reliability are paramount. This role requires a deep understanding of JVM internals, concurrency, networking, memory management, and Linux-based performance tuning. Key Responsibilities * Design and develop high-performance Java applications for low-latency environments. * Optimise JVM performance through advanced tuning, profiling, and troubleshooting. * Build resilient, event-driven and reactive systems capable of handling high transaction volumes. * Analyse and improve system performance across application, JVM, operating system, and hardware layers. * Implement efficient concurrency models and low-latency messaging solutions. * Work closely with architecture and infrastructure teams to deliver scalable, production-ready solutions. * Conduct performance testing, benchmarking, and capacity planning. * Investigate and resolve latency bottlenecks across distributed systems. Essential Skills & Experience * Expert-level Java development experience. * Proven experience with JVM performance tuning and optimisation. * Strong understanding of Data Structures and Algorithms. * Experience developing low latency, high throughput, event-driven systems. * Extensive knowledge of: * Concurrency and multithreading * Garbage Collection (GC) * JNI (Java Native Interface) * Java Unsafe * JNR-FFI * Experience building systems that operate within demanding latency constraints. Must Have Experience: * ✅ Strong Core Java Development * ✅ JVM Performance Tuning * ✅ Low Latency / High Performance Systems * ✅ Concurrency & Multithreading * ✅ Data Structures & Algorithms * ✅ Networking * ✅ Linux Nice to Have * Experience with Aeron messaging framework. * Exposure to financial trading, market data, or high-frequency systems. * Knowledge of distributed systems and messaging technologies. * Familiarity with modern observability and monitoring platforms