Principal Java Developer – Major Financial Institution London / Hybrid | Contract | £700-£800 inside IR35 (gross umbrella rate) We’re working with a major financial institution looking to scale out its engineering function with a Principal Java Developer to lead critical systems work. This is a hands-on Principal role requiring an experienced engineer with a finance background to come in and stabilise an existing platform. This Java-based stabilisation/ rescue project is expected to last at least a year, but the successful candidate will then be involved in the replatforming project. The replatforming project will be C#, and whilst you don't need C# experience to be successful, you should be happy to pick up the language moving forward for this role to be a fit. You’ll be working closely with infrastructure, architecture, and infosec teams to support high-availability production systems. The role also involves guiding CI/CD improvements, REST API design, and steering collaborative technical decisions across squads. What they’re looking for: Proven experience supporting large-scale, business-critical systems in the finance industry (all areas of finance considered) Strong background in Java and ideally C# Some front-end exposure in Angular - this is mandatory, but doesn't need to be recent or extensive Comfortable working with legacy systems and large enterprise environments Confident in leading technical conversations across multiple engineering disciplines Experience with CI/CD pipelines and modern deployment practices REST API design This is a great opportunity for an experienced Java Developer to join a prestigious financial player. If you’re someone who thrives in complex environments and enjoys technical leadership alongside delivery, apply now for a fast turnaround - this is an urgent project, so you'll need to be available in the next few weeks.