Senior Frontend Systems Engineer (TypeScript) – UI Frameworks | London
£150,000 – £200,000 + pension, private healthcare, gym membership, hardware budget
London (Hybrid – 2 days WFH)
Most frontend roles sit on top of frameworks.
This one builds them.
A high-growth software company is engineering a next-generation UI framework and data visualisation platform used in mission-critical environments by global enterprises, financial institutions, and technology companies.
Their products power applications used by millions of users every day.
This is not typical web development. You’ll be working at the level where performance, architecture, and browser behaviour actually matter.
What you’ll be doing
- Designing and optimising the core runtime of a high-performance JavaScript/TypeScript library
- Working directly with the browser rendering pipeline to handle large, real-time datasets
- Solving complex problems around data structures, recursion, memory usage, and rendering performance
- Building features end-to-end — from design through to release
- Contributing to a product used by engineering teams globally
What they’re looking for
- Strong, hands-on experience with JavaScript and TypeScript (framework-agnostic mindset)
- Background in C++, Java, or C# — or a clear systems-level way of thinking
- Solid understanding of algorithms, data structures, and performance optimisation
- Experience building complex systems (not just standard web apps)
- Good understanding of how frameworks (React, Angular, Vue) interact with the DOM
- Ability to identify bottlenecks, debug performance issues, and optimise effectively
- High standards around code quality, design, and maintainability
Why this role stands out
- You’ll work on problems most frontend engineers never get near
- You’ll be part of a deeply technical, engineering-led team
- High autonomy, low bureaucracy
- Real impact on a product used globally
Package includes
- £150,000 – £200,000 base salary
- Private healthcare
- Pension
- Gym membership
- 25 days holiday + bank holidays
- High-spec hardware
- Central London office (hybrid working)
If you want to engineer the foundations behind some of the world’s most demanding applications, this is the environment built for you. Get in touch!
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