Senior Software Engineer (Java & Performance)

, tax-free We're partnering with an innovative technology company that's helping organisations around the world make their digital platforms more secure, seamless and reliable. Their technology supports millions of digital interactions, where speed, security and reliability are essential. Operating across cloud, on-premise and highly secure environments, they're tackling engineering challenges that go far beyond traditional software development. And that's where this opportunity gets interesting. They're investing in the performance and scalability of their platform, creating an opportunity for an experienced engineer to work on complex technical challenges and make a real difference to how their systems operate. You'll join a talented engineering team where your work will directly influence the speed, efficiency and reliability of technology that people depend on every day. About the Role We're looking for a Senior Software Engineer specialising in Java and Performance Engineering to help optimise the speed, scalability and efficiency of a complex, distributed platform. You'll work across the entire technology stack, from Java and JVM internals to Kubernetes, networking and databases, identifying bottlenecks and developing solutions that improve performance in production. This is an opportunity to go beyond everyday backend development and tackle engineering problems where even small improvements in latency, throughput and resource efficiency can make a meaningful difference. You'll collaborate with experienced engineers, influence technical decisions and help establish performance practices that benefit the wider engineering team. Responsibilities • Improve application performance, optimising latency, throughput and resource usage across Java-based distributed systems. • Investigate performance bottlenecks, using profiling and benchmarking tools to identify issues across the JVM, Kubernetes, networking and databases. • Develop automated performance tests, helping identify regressions early in the development process. • Optimise Java and JVM performance, including garbage collection, memory usage, concurrency and thread management. • Improve system scalability, working on caching, database queries, connection pools and application configurations. • Support performance across cloud and on-premise environments, ensuring applications run efficiently on different infrastructure. • Contribute to capacity planning, helping teams understand infrastructure requirements and improve resource efficiency. • Collaborate with engineering teams to share performance insights, improve development practices and build reusable tools. Requirements • 8+ years of professional experience working with Java and JVM-based technologies in production environments. • Strong hands-on experience with Java 17/21 and Spring Boot. • Deep understanding of JVM internals, including garbage collection, memory management, concurrency and performance tuning. • Experience investigating and improving application performance, latency and throughput. • Familiarity with Java profiling and benchmarking tools, such as Java Flight Recorder, async-profiler, JMH, Gatling or k6. • Strong understanding of distributed systems, microservices and backend architecture. • Experience with Kubernetes and applications deployed across cloud or on-premise environments.