Senior C#/.NET Software Engineer

A rare opportunity to join a highly successful quantitative investment fund as a Senior Software Engineer, working at the heart of a technology-driven trading environment. Our client is a highly respected quantitative investment firm with a strong track record and a technology-first culture. They are now looking to hire an exceptional Senior Software Engineer with strong C#/.NET experience to join their growing engineering team in London. This is a particularly interesting opportunity for an engineer who wants to move beyond traditional software development and work on complex, high-performance systems where technology has a direct impact on investment performance. You’ll work alongside experienced software engineers, quantitative researchers and other technical specialists, solving challenging problems across performance, scalability, data and distributed systems. As a Senior Software Engineer, you'll take ownership of the design and development of critical systems supporting the firm's quantitative investment strategies. You’ll be involved across the full engineering lifecycle — from understanding the problem and shaping the architecture, through to implementation, optimisation and production. Your responsibilities will include: Designing and developing high-performance C#/.NET systemsBuilding scalable applications and services used by quantitative and investment teamsWorking closely with quantitative researchers to translate complex ideas into robust production softwareDesigning systems capable of processing significant volumes of dataInvestigating and resolving complex performance and scalability challengesApplying modern software engineering principles to build highly reliable systemsContributing to architectural and technology decisionsImproving engineering standards, development practices and toolingMentoring less experienced engineers and helping shape the technical direction of the team We're looking for a strong software engineer who enjoys working on technically demanding problems and has developed significant expertise in C# and .NET. You'll ideally have: Extensive commercial experience with C# and .NETStrong understanding of modern C#, including concurrency, asynchronous programming and performance optimisationExcellent knowledge of algorithms, data structures and software designExperience designing and developing complex, production-grade systemsStrong understanding of distributed systems and scalable architecturesExperience working with databases and high-volume dataA strong focus on code quality, testing and maintainabilityExperience diagnosing and optimising performance-critical applicationsExcellent problem-solving and communication skillsExperience within quantitative finance, trading, financial markets, low-latency systems or high-performance computing would be advantageous, although our client is also very interested in engineers coming from other technically demanding environments. The technology The core technology stack is C#/.NET, supported by a modern engineering environment. Depending on your area of focus, you may work with technologies including: C# · .NET · SQL · Linux · Azure · Docker · Kubernetes · Kafka · Distributed Systems · CI/CD ·