Senior Java Engineer (Low Latency / Trading Systems) - £950-1150/Day Outside IR35 Contract at Owen Thomas | Pending B Corp™, London Area, £950-£1150 per day

Senior Java Engineer (Low Latency / Trading Systems) - £950-1150/Day Outside IR35 Contract

London (Hybrid) | High-Performance, Real-Time Platform

We’re working with a high-performing engineering team building real-time, high-throughput systems at the core of a complex trading and data platform.

This is a hands-on contract role focused on designing and optimising low latency Java systems that process live market data, power pricing and risk engines, and support high-frequency decision-making.

You’ll be operating in an environment where performance is critical, latency is measurable, and engineering quality directly impacts production systems.

What you’ll be working on

• Building and optimising low latency, high-throughput Java systems for real-time data and trading workflows
• Designing components within a distributed, event-driven architecture handling large-scale streaming data
• Developing pricing, risk, and data processing systems used in live environments
• Applying advanced techniques in concurrency, GC tuning, memory management, and performance optimisation
• Improving system performance across latency, throughput, and reliability constraints
• Contributing to architecture across data pipelines, streaming systems, and backend services
• Supporting and enhancing production systems in time-critical scenarios

Core requirements

• Strong experience building low latency systems in Java (ideally Java 17/21+)
• Proven background in high-performance, data-intensive or trading systems
• Deep understanding of JVM internals, concurrency, and performance tuning
• Experience designing and building distributed systems at scale
• Strong experience with real-time data processing and event-driven architectures (e.g. Kafka or similar)
• Ability to reason about latency vs throughput vs consistency trade-offs
• Comfortable working in production-critical environments with real-time constraints

Highly desirable

• Experience with Aeron, Chronicle or LMAX disruptor
• Experience in electronic trading, pricing, or risk systems
• Knowledge of FIX protocol, order routing, or market connectivity
• Exposure to high-frequency or ultra-low latency environments
• Experience working closely with Quants or front-office stakeholders
• Background across asset classes such as FX, Equities, Commodities or Derivatives

Tech environment (indicative)

• Java (core), JVM ecosystem
• Distributed systems, microservices, event-driven architecture
• Streaming technologies (Kafka or equivalent)
• Real-time data pipelines
• Cloud infrastructure (AWS / GCP)
• Observability, performance monitoring, and diagnostics tooling

The environment

• Engineering-led, performance-focused culture
• Fast-paced environment with real production impact
• Close collaboration with quantitative and trading teams
• Hybrid working model (London-based) - 2-3 days per week required in office

Why this contract?

This is a role for engineers who care about how systems behave under pressure.

You’ll be working on platforms where:

• Milliseconds (and often microseconds) matter
• System performance is constantly measured and improved
• Your work directly impacts real-time decision making

If you’ve built low latency systems and want to work closer to real trading environments, this is a high-impact contract opportunity.