Software Engineer - High-Performance Java / Low Latency

Randstad Technologies; City Of London; Hybrid; GBP 95,000 - 140,000; Full time

Job summary

Randstad Technologies in London, UK is seeking a Software Engineer to join on a contract (Inside IR35) basis, focusing on high-performance Java and low-latency trading platforms for agency liquidity expansion.

You will design and optimize high-throughput, low-latency systems, perform JVM tuning and memory profiling, develop low-level Java solutions with Unsafe/JNI/JNR-FFI, and collaborate across cross-functional teams to deliver key regional projects.

Qualifications

• Expertise in Java high-performance engineering and JVM tuning.
• Experience with low-level Java APIs (Unsafe, JNI, JNR-FFI) and memory concerns.
• Strong understanding of event-driven design and concurrent programming.

Responsibilities

• Design, build, and optimize high-throughput, low-latency systems.
• Tune GC and profile memory for ultra-low latency.
• Implement low-level Java solutions using Unsafe/JNI/JNR-FFI.
• Collaborate with cross-functional teams on regional project deliverables.

Skills

Core Java

JVM Internals

GC Tuning

Low-Level Java APIs

JNI/JNR-FFI

Concurrency

Networking

Tools

Aeron

Linux

Job description

Software Engineer - High-Performance Java / Low Latency

Role Type: Contract (Inside IR35)

Location: London, UK (Hybrid - 3 days per week in-office)

Overview

We are looking for a specialist High-Performance Java Engineer to join our team in London, focusing on the expansion of Agency Liquidity based on Principal Risk. In this role, you will work closely with CRB to drive key EMEA and US regional projects, developing low-latency, event-driven trading platforms.

Core Responsibilities

• Design, build, and optimize high-throughput, low-latency concurrent systems for agency liquidity expansion.
• Perform fine-grained JVM tuning, garbage collection (GC) optimization, and memory profiling to achieve ultra-low response times.
• Engineer low-level Java solutions utilizing JNI, Java Unsafe, or JNR-FFI for high-frequency processing.
• Collaborate across cross-functional engineering and risk teams to execute high-impact EMEA and US project deliverables.

Technical Requirements

• Core Java & JVM: Deep expertise in Java high-performance engineering, JVM internals, garbage collection strategies, and profiling.
• Low-Level & Hardware Optimization: Solid foundation in low-level Java APIs (Unsafe, JNI, JNR-FFI), CPU architecture, shared memory, and memory-mapped files.
• Architecture & Concurrency: Mastery of event-driven/reactive designs, multi-threading, concurrent programming patterns, and core Data Structures & Algorithms.
• Networking & OS Internals: Strong hands-on knowledge of networking protocols (TCP/UDP, low-latency socket programming) and Linux kernel/memory management.

Technical Nice-to-Have

• Hands-on experience with the Aeron messaging framework or similar ultra-low-latency messaging technologies.