Senior Software Engineer

Software Engineer | C#, SQL, Legacy Refactoring | Systematic Hedge Fund Rate: £650-750 per day IR35: Outside Duration: 12 months Location: 3 days in the office per week in Moorgate/Liverpool Street We’re working with a high-performing, systematic hedge fund based in the City to help them hire a Senior Software Engineer to take ownership of a core Portfolio Management platform during a major platform migration and refactor initiative. This is a unique opportunity to own and evolve a mission-critical application in a lean, engineering-led environment where quality matters and your input will directly shape the platform’s future. Environnent & Culture: 3 days a week in-office (typically Mon/Wed/Fri) - ESSENTIAL Based in a central London WeWork office with access to a nearby front-office floor Very lean team, just 16 people globally 8 of whom are in technology Fast decision-making, lots of autonomy, very high standards Expect collaborative discussion and plenty of technical back-and-forth Tech Stack: C# / .NET (currently on 4.6.1, migration planned) SQL Server (Any RDBMS experience is ok) Python (nice to have) Docker (nice to have some containerisation appreciation) CI/CD, monitoring, observability (nice to have) Experience in XP or lean development (nice to have) The Role: You’ll be the lead engineer on their Portfolio Management application , refactoring the existing codebase, helping move it to a new server environment, and improving how logic sits between the app and the database. The application is mature but under-tested so the focus is on precision refactoring , incremental improvement , and maintaining behavioural integrity during change. You'll work closely with senior platform owners, quant developers, a DevOps engineer, and trading analysts across the front and middle office. About You: 10 years’ experience as a hands-on software engineer Strong C#/.NET and SQL background, ideally in data-centric or financial systems Solid experience refactoring legacy applications without full test coverage Testing; You must be a meticulous Tester in TDD. Excellent at writing characterisation tests to lock down behaviour before improving You must have a passion for refactoring to improve code quality and for automated testing at all levels; unit, integration & acceptance. You take pride in annotated, clean commits and structured workflows Having a ‘DevOps mindset’ and getting the importance of culture If you enjoy carefully improving legacy code , owning your application, and collaborating closely with a brilliant (and refreshingly small) trading and quant team, this one’s for you. Apply ASAP for an immediate interview! Software Engineer | C#, SQL, Legacy Refactoring | Systematic Hedge Fund