C# / .NET Developer – Front Office, Electronic & Low Latency Trading Systems

Join MARGO in the UK (London) – Perm & Contracting Opportunities. MARGO is a tech-native consultancy delivering high value-added IT expertise to the financial services industry. We specialise in complex software engineering environments where performance, robustness and scalability are critical: real-time systems, low-latency architectures, distributed computing and high-throughput data processing. Joining MARGO means working in demanding Front Office and Trading IT environments, while benefiting from a human-sized structure, close follow-up and tailor-made training paths.

Responsibilities

Design, develop and maintain high-performance C# / .NET applications; Work on real-time data processing including market data, pricing, orders, analytics and risk calculations; Implement concurrency and parallel programming patterns adapted to performance-sensitive systems; Participate in system design, architecture discussions and technical specifications; Continuously optimise performance including latency, throughput and memory usage; Contribute to the full software lifecycle: design, development, testing and release; Produce clean, maintainable and well-tested code; Participate in sprint planning, estimations and technical reviews; Collaborate closely with developers, quant and infrastructure teams; Provide 3rd line support on production systems when required; Participate in production releases including occasional out-of-hours interventions; Contribute to system stability, monitoring and incident prevention

Requirements

C# / .NET (expert level); Concurrency and parallel programming; Asynchronous and multithreaded models; Memory management and performance profiling; Distributed and event-driven architectures; Windows and/or Linux production environments; Performance monitoring and profiling tools; Strong experience as a C# / .NET Developer in performance-sensitive environments; Proven background in real-time or high-throughput systems; Solid understanding of concurrency, parallelism and memory optimisation; Experience working in Front Office, Trading or Risk IT environments; Strong production mindset and system ownership; Clear communication and structured problem-solving skills

Nice to have

Exposure to electronic trading platforms or low-latency environments; Experience across one or more asset classes (Equities, Fixed Income, Commodities, FX, Derivatives); Familiarity with distributed, grid or event-driven systems; Interaction with C++ low-latency or HFT-adjacent components; Electronic trading or low-latency trading systems; High-throughput or real-time architectures; Messaging middleware (Kafka, Solace or equivalent); FIX or other market connectivity protocols; RESTful or service-oriented architectures; High Performance Computing (HPC) or grid computing concepts

Benefits

Access to multi-asset Front Office, Trading and Electronic Trading environments; Highly technical and challenging engineering assignments; Clear positioning between HFT and non-HFT trading systems; Strong emphasis on skill development and long-term career progression; Human-sized consultancy with close support and high-quality missions; Tailor-made training paths