Front-End Developer – React or Angular (Front Office & Risk Systems)

Join MARGO in the UK (London) – Permanent & Contracting Opportunity. MARGO is a tech-native consultancy delivering high value-added IT expertise to the financial services industry. We operate in complex Front Office and Risk environments where user interfaces are critical components of trading, risk and decision-making systems. Our consultants design and build high-performance, real-time and maintainable UI platforms used daily by Front Office, Risk and technology teams. Joining MARGO means working on technically demanding UI platforms, close to business users, while benefiting from a human-sized structure, strong engineering standards and tailored career paths.

Responsibilities

Design and develop high-performance front-end applications using React or Angular; Own UI architecture, component design and state management; Build data-intensive and real-time user interfaces; Ensure scalability, maintainability and long-term evolvability of UI platforms; Apply best practices around clean code, refactoring and testing; Develop UIs consuming real-time or near real-time data streams; Manage high-frequency UI updates and rendering efficiency; Optimise performance under real-time constraints; Control latency perception, responsiveness and user experience; Work with event-driven and streaming data sources; Work closely with backend teams to define and consume APIs; Collaborate with production, infrastructure and QA teams; Translate business and user needs into robust UI solutions; Act as a technical reference on front-end topics within the team; Enforce high standards for code quality, testing and documentation; Participate in code reviews and architectural discussions; Contribute to continuous improvement of front-end practices and tooling; Support mentoring and knowledge sharing while remaining hands-on

Requirements

Strong experience as a Front-End Developer on complex web applications; Expert-level proficiency in either React or Angular (one mandatory); Solid understanding of front-end architecture and design patterns; Experience building scalable and maintainable UI platforms; Strong attention to performance and user experience; Ability to work in demanding Front Office or Risk environments; Excellent communication and collaboration skills; TypeScript and modern JavaScript; State management (Redux, NgRx or equivalent); HTML5, CSS3 and modern styling approaches; Component-based architecture and modular design

Nice to have

Real-time UI patterns (WebSockets, streaming APIs or equivalent); Data grids and complex visual components; Performance profiling and optimisation techniques; Modern build tools and frameworks (Vite, Webpack or equivalent); Unit and integration testing frameworks; Exposure to Front Office, Risk or real-time systems; Experience working on data-intensive or analytical UIs; Familiarity with real-time communication patterns; Mentoring or technical leadership experience

Benefits

Access to complex Front Office and Risk UI platforms; Strong emphasis on engineering quality and clean front-end architecture; Real-time, performance-sensitive UI challenges; Human-sized consultancy with close support and long-term focus; Long-term career opportunities across engineering and architecture