Java Engineer - Low Latency

Juxt Ltd.; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Juxt Ltd. in London is seeking Java Developers to join a high-performance, low-latency trading and real-time data project for a major financial institution. You will write and tune Java frameworks, optimize throughput and latency, and apply event-driven microservice architectures.

You will work with peers to design robust, measurable software, dive deep into JVM and Linux performance, and help push systems that power global markets. Hybrid role with on-site work at Canary Wharf.

Qualifications

• Proven experience building or optimizing low-latency systems.
• Strong Java skills with deep JVM knowledge.
• Experience with multithreading and memory management.
• Experience with microservice architectures and event-driven systems.

Responsibilities

• Write and tune high-performance Java frameworks to reduce latency.
• Improve throughput and latency for critical, real-time data applications.
• Collaborate with engineers to design elegant, performance-focused solutions.

Skills

Java proficiency

JVM expertise

Low-latency experience

Performance tuning

Multithreading

Microservices

Linux familiarity

Clear communication

Tools

JMH

async-profiler

Flight Recorder

Job description

Job Description

We’re looking for Java Developers with experience building low-latency systems to join us on a high-performance trading and real-time data project, for a major financial institution.

You’ll work on mission-critical applications where performance, scalability, and reliability truly matter — the kind of systems that power global trading platforms and require a deep understanding of how the JVM and Linux really work. This is an opportunity to bring world-class engineering principles to projects at the very heart of modern finance.

Your work will focus on writing and tuning high-performance Java frameworks, improving throughput and latency, and applying event-driven, microservice-based architectures. You’ll collaborate closely with other talented engineers, helping to shape elegant solutions to complex, performance-sensitive problems.

You’ll be joining an environment where good software engineering truly matters — where clean design, measurable performance, and deep system understanding are valued. This is an opportunity to work alongside recognised low-latency specialists, elevate your expertise, and contribute to systems that demand precision and technical excellence.

We’re looking for developers who are technically exceptional, but also pragmatic — engineers who love to understand how things work under the hood, measure performance precisely, and continuously refine their craft.

Core skills

• Strong Java skills with deep knowledge of the JVM
• Proven experience building or optimising low-latency systems
• Familiarity with performance tuning and profiling tools (e.g. JMH, async-profiler, Flight Recorder)
• Solid understanding of multithreading, concurrency, and memory management
• Experience with microservice architectures and event-driven systems
• Linux fundamentals and comfort with performance diagnostics
• Clear communication skills and ability to articulate design and performance decisions

Nice to have

• Experience with high-performance messaging (Chronicle Queue/Wire, Aeron, ZeroMQ, Kafka tuning)
• Familiarity with off-heap or direct memory structures (Chronicle Map, VarHandles, DirectByteBuffers)
• Networking/I/O frameworks such as Netty or custom FIX engines
• Exposure to OpenHFT, LMAX Disruptor, or similar performance-focused frameworks
• Prior experience in trading, financial markets, or real-time data systems
• Ability to produce clear, lightweight documentation or UML diagrams when needed

WFH?

These roles are hybrid - a mix of working from home and on-site collaboration in London, Canary Wharf.

Contract type

Both permanent and contract arrangements considered.

Eligibility

We can only consider candidates who have the right to work in the UK and do not require visa sponsorship. Applicants must be UK-based and within a commutable distance to London.