Principal Software Engineer
Principal UI Engineer (React) — Confidential Client | Hybrid, Belfast
Our client is one of the world's largest interdealer brokers and data providers, operating at the centre of global financial markets. Their Belfast engineering hub is home to some serious technical talent — and they're now looking for a Principal UI Engineer to help lead the way on the front end.
This is a senior individual contributor role with real influence. You'll be setting the standard for how complex, data-intensive UIs are built and maintained — working on platforms that traders, brokers, and financial professionals rely on every day.
What you'll be doing
- Leading front-end architecture decisions across mission-critical trading and data platforms
- Building and maintaining high-performance React applications that handle complex, real-time financial data
- Setting coding standards, conducting deep-dive code reviews, and raising the bar across the UI engineering team
- Collaborating closely with product, design, and backend engineers to deliver seamless end-to-end experiences
- Mentoring senior engineers and acting as the go-to voice on all things front end
- Evaluating new tooling and frameworks, and making the case for where the stack should go next
What we need
- Expert-level React — you know it inside out, including performance optimisation, state management, and component architecture at scale
- A strong grasp of modern JavaScript/TypeScript and front-end fundamentals
- Experience working on complex, data-heavy applications — ideally in financial services or similarly demanding domains
- The ability to lead technically without being in a management role — you influence through expertise
- Comfortable in a hybrid environment, with regular presence at the Belfast office
Nice to have
- Exposure to real-time data, WebSockets, or market data feeds
- Experience with design systems or component libraries at scale
- Familiarity with the broader interdealer broker landscape
If you're a front-end engineer who wants to operate at principal level on genuinely complex problems — not just maintain a marketing site — this one's for you. Reach out to Brendan directly.