Senior Frontend Engineer (Product) - AI SaaS - London (Hybrid)

Stax is proud to be representing a leading, well-funded AI-driven SaaS company that is redefining the future of work.

This organisation is building an AI-native platform that unifies data, drives intelligent insights, and empowers collaboration across teams and customers. Its mission is to remove friction, break down silos, and enable people to focus on solving bigger problems, building better products, and delivering exceptional customer experiences.

What Youll Do

• Architect the platform: Define patterns, conventions, and tooling that keep the React + TypeScript codebase fast, modular, and maintainable.
• Evolve design systems: Lead on design tokens, accessibility standards, and Storybook workflows to drive consistency and speed in development.
• Scale data-driven UIs: Build frameworks for rendering billions of rows, real-time charts, and AI-assisted insights while maintaining Core Web Vitals.
• Enhance developer experience: Champion CI/CD pipelines, testing strategies, and local development ergonomics to enable engineers to ship quickly and confidently.
• Mentor and uplift: Coach senior engineers, review critical code, and run architecture workshops to raise the overall engineering bar.
• Collaborate deeply: Partner with cross-functional teams to translate complex, ambiguous problems into elegant, scalable solutions.

Tech Ecosystem

React TypeScript Vite Next.js WebAssembly (DuckDB, WebGPU) D3/visx Storybook Tailwind CSS Jest Cypress Playwright

What You Bring

• 8+ years building and evolving large-scale web applications.
• Proven track record in front-end architecture (modular codebases, micro-frontends, design systems, scalability).
• Strong portfolio of data-heavy, real-time UIs and reusable component libraries.
• Expertise in TypeScript, CSS methodologies (Tailwind, CSS Modules, CSS-in-JS), and modern testing frameworks.
• Passion for developer experience, tooling, and mentoring.
• Degree in Computer Science or equivalent experience.

Bonus points for:

• Open source contributions to front-end tooling, design systems, or data-visualisation libraries.
• Experience with WebSockets, PWAs, offline support, or design-token pipelines.

How They Work

• Speed with craftsmanship: Continuous delivery, short feedback loops, and peer review excellence.
• Performance first: Time-to-Interactive, bundle size, and UX performance are treated as product metrics.
• Inclusive and global: Work with talented engineers across the US, Europe, and India.
• Ownership culture: Engineers architect, guide, measure, and iterate with autonomy.

Why Apply?

This is a chance to join a hyper-growth company at the forefront of AI-powered collaboration, tackling some of the most exciting challenges in front-end engineering today.

Interested? Reach out to Stax for a confidential discussion.

Please be advised that, owing to the expected volume of applications, we may only be able to contact candidates selected for further consideration.