Avanti Recruitment is working with a long-established and award-winning UK FinTech firm based in Surrey. They have commodity trading platforms and are now looking to hire a mid-level Java Developer to join their small, collaborative software team. This is a hands-on role with a strong focus on maintaining and improving a long-standing Java system, while also contributing to the company's journey towards a modern, microservices-based architecture. The successful candidate will spend approximately 70–80% of their time working on legacy systems (Java 8) and the remainder on newer microservices projects (Java 17/21). The company values real-world problem-solvers who are comfortable getting stuck into older codebases and keeping business-critical systems running smoothly. What You'll Be Doing: * Enhancing and supporting legacy Java applications * Participating in the gradual migration to microservices using Spring Boot and AWS * Taking ownership of tasks across the full SDLC — from development and integration to bug fixing and support * Working closely with internal stakeholders including trading teams, product owners, and the Head of IT * Handling occasional production support issues, context switching between projects and urgent tasks What they’re looking for: * 3–5 years of Java development experience * Previous experience working on legacy or monolithic systems * Strong Java fundamentals and understanding of OOP * Familiarity with Spring / Spring Boot and REST APIs * Experience working with SQL databases (MySQL / PostgreSQL) * Comfortable working in small teams and wearing many hats * Proactive, self-sufficient, and able to work with minimal supervision Desirable (Not Essential): * Exposure to AWS (Aurora, Lambdas, EC2) * CI/CD (Jenkins or GitHub Actions) * Containerisation (Docker) * Front-end knowledge (React or similar) * Prior experience in finance or high-availability transactional systems Benefits: * Salary up to £70,000 * 27 days holiday bank holidays * Private medical cover (post-probation) * Life insurance and pension * Hybrid working: 3 days in the office (Mon/Tue/Thu), 2 days remote * Free parking near the office This role is not greenfield or bleeding-edge. The team are honest and transparent: there’s a lot of legacy work, but it’s stable and business-critical. If you enjoy solving tough problems in real systems, working in tight-knit teams, and gradually modernising infrastructure the right way, then this role could suit you. If you are interested in applying then click Apply Now