Java Low Latency Engineer in London, Greater London

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.