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

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. Business Context You will join the Front Office / Trading IT environment of one of our tier-1 investment banking or trading partners. The teams design and maintain mission-critical C# / .NET systems supporting electronic trading, real-time risk and analytics platforms across multiple asset classes (Equities, Fixed Income, Commodities, FX, Derivatives). These systems operate close to trading desks and electronic trading platforms, with strong constraints on performance, reliability and production stability. The environment is characterised by:

• Real-time and event-driven architectures

• Low-latency and high-throughput processing requirements

• Strong production and stability constraints

• Close interaction with trading, quantitative and risk teams

• High engineering standards and short delivery cycles, We are looking for an experienced C# / .NET Developer to work on real-time, electronic trading and risk systems. The role is primarily technical and engineering-driven, focused on performance, scalability and robustness rather than business analysis. Candidates are expected to have prior exposure to Front Office, Trading or Risk environments, regardless of the underlying asset class., Design & Development

• 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

Engineering & Delivery

• 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

Production & Support

• 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

Technical Environment Core Technologies

• 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

Valued Technical Exposure

• 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

Do you have experience in REST?, * 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

Valued (but not restrictive)

• 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