Full Stack Developer | C#/.NET with React | Global Trading Firm | 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, optimisation, and decision-support systems used directly by front-office, fiscal, commercial, and operational teams.
The environment is high-performance, low-bureaucracy, and focused on solving complex, real-world problems where accuracy, speed, clarity, and commercial impact genuinely matter.
The firm is now looking for a Full Stack Developer with a strong mathematical, analytical, or quantitative background to help build and scale platforms that support complex modelling, forecasting, optimisation, and decision-making workflows.
This role is ideal for someone who enjoys combining serious problem-solving with modern software engineering, working across C#/.NET backend services and React frontends, and who is comfortable working with complex data, models, business logic, constraints, and numerical accuracy.
You do not need to be a quant developer, but you should enjoy working close to mathematical problems, optimisation logic, and business-critical analytical systems.
London City, hybrid working
Highly competitive base + bonus + benefits package
What You’ll Be Doing
* Build and evolve end-to-end analytics and decision-support applications using C#/.NET and React.
* Design performant backend services and APIs that support data-heavy, computation-driven use cases.
* Create clear, intuitive React UIs that expose complex datasets, workflows, scenarios, and modelling outputs.
* Work closely with traders, analysts, fiscal, finance, commercial, and operations teams to translate quantitative and business requirements into production systems.
* Contribute to optimisation-focused tooling, including models involving constraints, scenarios, allocation, forecasting, and decision-support logic.
* Apply strong engineering principles to problems where correctness, performance, and clarity genuinely matter.
* Contribute to system design, architecture discussions, code reviews, and wider technical decisions.
* Bachelor’s or Master’s degree in Mathematics, Applied Mathematics, Computer Science, Engineering, Physics, Operations Research, or a similarly quantitative discipline.
* At least 5 years of strong commercial experience with C# and .NET, including ASP.NET Core and Web APIs.
* At least 5 years of strong experience with React and modern frontend development, with the ability to build clean, maintainable, data-driven user interfaces.
* Strong mathematical or analytical problem-solving ability, with confidence working around numerical data, models, constraints, edge cases, and correctness.
* Exposure to linear programming, mathematical optimisation, operations research, modelling, forecasting, or decision-support systems.
* Solid understanding of data structures, algorithms, and computational problem-solving.
* Experience working with relational databases and SQL, such as SQL Server, PostgreSQL, or Oracle.
* Ability to work closely with both technical and non-technical stakeholders, including fiscal, finance, commercial, trading, analytical, or operational teams.
* Strong communication skills and a pragmatic engineering mindset.
Nice to Have
* Experience in trading, commodities, financial services, analytics platforms, or commercial optimisation environments.
* Hands-on exposure to optimisation libraries, solvers, or modelling tools.
* Experience with event-driven systems, messaging, async workflows, or concurrent systems.
* Experience building tools used by fiscal, finance, trading, analytics, or commercial teams.
What’s in it for you?
* Work on high-impact systems used by teams making real commercial decisions.
* Solve interesting, non-trivial engineering and mathematical problems - not just CRUD and UI tickets.
* Partner directly with commercial, fiscal, operational, and quantitative teams.
* Build software where performance, usability, numerical accuracy, and business impact all matter.
* Collaborate with highly skilled engineers and analytical professionals.
* Competitive base salary, bonus, benefits, and a strong long-term engineering culture.
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