Senior / Principal Java Developer

We are looking for multiple Senior and Principal Java Developers to join a high-performing engineering team responsible for building next-generation electronic trading technology. This is an opportunity to work on business-critical, ultra-low latency trading systems where performance, reliability and scalability are fundamental. You'll design and develop sophisticated event-driven platforms, optimise system performance at every layer of the stack, and help shape the architecture of complex distributed applications used across global financial markets. We're looking for engineers who are passionate about writing exceptional Java, enjoy solving complex performance challenges, and have a deep understanding of how software interacts with hardware, operating systems and networks.

You'll be a passionate engineer who enjoys solving complex technical problems and takes pride in producing elegant, high-quality software. You'll have a collaborative approach, thrive in highly technical environments, and be motivated by building systems where every microsecond matters.

Responsibilities

• Design and develop ultra-low latency Java applications and frameworks.
• Build scalable event-driven microservices supporting mission-critical trading platforms.
• Analyse, benchmark and optimise application performance across the JVM, operating system and network stack.
• Design clean, maintainable and scalable software architectures.
• Implement high-quality, production-ready software following engineering best practices.
• Participate in architectural discussions and contribute to technical strategy.
• Produce clear technical documentation, including UML sequence diagrams where appropriate.
• Collaborate closely with software engineers, architects and business stakeholders to deliver robust solutions.

Requirements

• Expert-level Java development experience.
• Proven commercial experience building low latency, high-performance applications.
• Deep understanding of:

• Modern Java
• JVM internals
• Linux operating systems
• Concurrency and multithreading
• Performance profiling and optimisation

• Strong software architecture and design skills.
• Experience delivering complex software projects throughout the full development lifecycle.
• Excellent communication skills with the ability to explain complex technical concepts clearly.

Experience with any of the following is highly desirable

High-Performance Messaging

• Chronicle Queue / Chronicle Wire
• Aeron
• Kafka (low-latency implementations)
• ZeroMQ

Memory & Performance

• Chronicle Map
• Direct ByteBuffers
• Off-heap memory
• Unsafe APIs / VarHandles

Networking

• Netty
• epoll / kqueue
• FIX Protocol
• QuickFIX/J
• SBE (Simple Binary Encoding)
• FIXP

Performance Engineering

• JMH (Java Microbenchmark Harness)
• Java Flight Recorder
• Mission Control
• async-profiler
• perf
• JVM GC tuning (ZGC, Shenandoah, G1)

Specialist Frameworks

• OpenHFT libraries
• LMAX Disruptor
• Aeron Cluster
• Lock-free queues and ring-buffer implementations

Desirable Experience

• Electronic trading or algorithmic trading platforms.
• FX trading systems.
• KDB+.
• Grafana.
• Experience with Ambrosia low-latency framework.