My client, a high-performing, data-driven hedge fund, is seeking a top-tier Graduate / Junior C# Developer to join their London-based technology team. This is a rare opportunity to join a lean, high-calibre environment where technology sits at the core of the business. The team is directly aligned to the trading function, building systems that process market data, support analytics, and enable trading decisions across fixed income markets. You will be working in a flat, agile team with real ownership from day one, contributing to a wide range of projects and actively participating in architectural discussions. The environment is fast-paced, with an iterative development cycle and weekly production releases, requiring engineers who are both pragmatic and delivery-focused. Key Responsibilities will include: Building and enhancing high-performance systems in C# supporting trading and analytics workflows Developing tools for market data processing, trading infrastructure, and internal platforms Working across the full development lifecycle: design, implementation, testing, and production support Collaborating closely with traders, quants, and engineers to deliver robust, scalable solutions Contributing to system architecture and design decisions from an early stage The team regularly tackles complex engineering challenges, including: State management and fault tolerance at scale Concurrency and race conditions Distributed compute and parallelisation Horizontal scaling and sharding Large-scale data processing A successful candidate will: Have an outstanding academic background (Computer Science, Maths, Physics or similar) Demonstrate strong experience with C# / .NET Possess a solid foundation in data structures, algorithms, and system design Show evidence of technical curiosity and extracurricular projects Be motivated to work in a high-performance, collaborative environment Exposure to financial markets (bonds, swaps, rates, FX) Experience with Python for data or quantitative work Familiarity with Linux environments You can expect: A high-impact role working directly with the trading function A flat structure with real ownership and responsibility Exposure to complex, non-trivial engineering problems at scale A fast-paced environment focused on continuous learning and improvement Highly competitive compensation and bonus structure To apply, either respond to this advert or send your CV directly to gala.santaballa@mondrian-alpha.com.