Job Description

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.
Key Responsibilities
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
Required Experience & Skills
Essential·        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
Why Join MARGO
·        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
Please note - We do not offer visa sponsorship for this position.
Interested? Motivated? Apply on our website or at staff.uk@margo.com

About MARGO

More than a simple IT consulting group, MARGO is an alchemy of talents with constantly enriched expertise, always encouraged to be dynamic and to flourish.

For more than 17 years, we have been carrying out missions of the highest technical complexity, enabling the digital acceleration of our clients, while ensuring a perpetual intellectual and collective stimulation for all our talents.

At MARGO it's Consultant First.

By joining MARGO, your talent today will remain relevant tomorrow. We bring you into the group not only for what you are today but for the potential you wish to develop.

At MARGO, you will be able to build your own path to excellence within our teams and our missions. Tailor-made to serve your ambition and to match your talent.

Today, Margo has over 400 employees in 8 entities:

► MARGO Trading Systems: our full stack development offer in market finance

► MARGO Capital Markets: our business offer in market finance

► MARGO Analytics: our expertise in data science and data engineering

► A CAPELLA Consulting: our business offer dedicated to insurance

► CODE BUSTERS: our community of developers

► DELIVERED by MARGO: our 100% remote full stack development entity

► MARGO UK: expertise in complex coding and application support on the English market.

► MARGO Poland: expertise in complex coding in retail Banking on the Polish market.

Industry

IT & Software

Company Size

201-500 employees

Headquarters

Courbevoie, FR

Year Founded

2005

Website

margo.com

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