Full Stack Developer | .NET & React | Financial Services | London, Hybrid

Full Stack Developer | .NET & React | Financial Services | London, Hybrid

Our client is a global, privately held firm operating in fast‐moving, data‐intensive markets. Technology is central to how the business runs, with engineers building analytics and decision‐support systems used directly by front‐office and operational teams.

The environment is high‐performance, low‐bureaucracy, and focused on solving complex, real‐world problems where accuracy, speed, and clarity genuinely matter.

The firm is now looking for a Full Stack Developer with a strong analytical or quantitative mindset to help build and scale the firm's analytics and decision‐support platforms.

This role is ideal for someone who enjoys combining serious problem‐solving with modern software engineering, working equally across C#/.NET backend services and React frontends, and who is comfortable working with complex data, models, and business logic.

What You’ll Be Doing

• Build and evolve end‐to‐end analytics applications using C#/.NET and React (roughly a 50/50 split)
• Design performant backend services and APIs that power data‐heavy, computation‐driven use cases
• Create clear, intuitive React UI s that expose complex datasets and workflows
• Work closely with traders, analysts, and operations teams to transform quantitative requirements into production systems
• Contribute to system design, architecture discussions, and code reviews
• Solve real‐world problems where correctness, performance, and clarity truly matter

📍London City, hybrid working

💷Highly competitive base + bonus + benefits package

⌛Permanent Role

Essential Requirements:

• Bachelor’s or Master’s degree in Mathematics, Applied Mathematics, Computer Science, or a similarly quantitative discipline.
• Strong commercial experience with C# and .NET (ASP.NET Core, Web APIs), building backend services for enterprise or analytical systems.
• Strong experience with React and modern frontend development, with the ability to build clean, maintainable, data-driven UIs.
• Solid understanding of data structures, algorithms, and computational problem-solving.
• Experience working with relational databases and SQL (e.g. SQL Server, PostgreSQL, Oracle).
• Comfortable reasoning about numerical data, models, edge cases, and correctness.
• Experience working in agile/scrum environments.
• Strong communication skills and the ability to engage directly with technically minded and non-technical stakeholders.

Nice to Have:

• Experience in trading, commodities, finance, or analytics platforms
• Exposure to event‐driven systems, messaging, or async/concurrent workflows
• Interest in optimisation, modelling, or decision‐support systems

What's in it for you?

• Work on high‐impact systems used by teams making real commercial decisions
• Solve interesting, non‐trivial problems - not just CRUD and UI tickets
• Collaborate with highly skilled engineers and quantitative professionals
• Competitive compensation and a strong, long‐term engineering culture

📧If you are interested in this Full Stack Developer Role in London, please apply directly to this advert with your updated CV or email it to chantelle.smith@sourcegroupinternational.com