We are supporting a leading global financial technology organisation who are looking for a highly technical Senior Java Performance Engineer to join a major Securities Finance Trading & Collateral platform team. This is a hands-on engineering role focused on building, optimising and rearchitecting performance-critical enterprise applications used by global financial institutions across the buy-side and sell-side markets. The environment is highly technical and engineering-led, so this role will suit someone who is actively coding in Java on a daily basis and has strong experience improving application scalability, throughput and performance within complex distributed systems. This is NOT a performance testing role. The focus is on deep Core Java engineering, optimisation and architectural performance improvements. The role will be based in London on a hybrid basis, with occasional travel to Zurich — expected to be the first 2 weeks initially, then typically 1–2 days per month thereafter. Key Responsibilities Design and develop high-performance enterprise Java applications Analyse and optimise performance-critical functionality across large-scale distributed systems Identify bottlenecks relating to memory, latency, throughput and scalability Drive architectural and performance improvements across the platform Work closely with architects and senior engineering teams on strategic platform initiatives Improve resilience, scalability and efficiency of core trading platform services Develop and enhance APIs and integration services Contribute within Agile / Scrum engineering teams using TDD best practices Support modernisation initiatives including cloud-native and containerised environments Required Skills & Experience Strong hands-on Core Java development experience (Java SE/JEE) Proven experience in Java performance optimisation and scalability engineering Excellent coding ability — this role requires someone who is actively developing day-to-day Strong SQL skills across Oracle, SQL Server or PostgreSQL Experience building enterprise-scale financial services applications Strong understanding of software design patterns and enterprise architecture principles Hands-on experience with: Spring Framework JMS & Middleware JPA / Hibernate REST APIs Experience with TypeScript and Angular (v2) Understanding of distributed systems and integration patterns Experience with Kubernetes and/or OpenShift Experience integrating with IAM technologies including OAuth, OpenID Connect and SSO Agile / Scrum and Test-Driven Development experience Nice to Have Securities Finance or Trading Platform experience Experience within Capital Markets or Financial Services environments Apache Camel or integration framework experience CI/CD and DevOps tooling exposure Experience modernising legacy enterprise platforms