Stackone
Senior UI Engineer
12mo ago
EuropeSeniorRemotereactapidesign systemsperformance optimizationfront-end
Senior UI Engineer responsible for front-end development, design systems, and performance optimization at StackOne's AI integration SaaS platform.
Requirements
- 4+ yrs professional front-end engineering with a portfolio that focus on the details.
- React & TypeScript at production scale; comfortable with hooks, suspense, and server components.
- Deep CSS fluency (Tailwind or equivalent) and experience of modern browser APIs.
- Proven track record building or migrating component libraries/design systems.
- Strong performance tuning instincts: Lighthouse, Core Web Vitals, bundle analysis, code-splitting.
- Familiarity with monorepo tooling (NX or Turborepo) and micro-frontend patterns.
- Ability to dive into back-end code (Node, React-router, sveltekit) to remove perf bottlenecks, instrument metrics, or adjust API shape.
Nice to have
- Svelte, Web Components, or other framework experimentation.
- Experience with auth flows (OAuth2, OpenID Connect) and secure front-end patterns.
- Web Motion & animation chops
- Prior work on B2B developer tools or dashboards at seed-to-Series-B stage.
Conditions
- Meaningful share options (EMI) - share in the company's success as we grow
- 25 days holiday + 1 additional day per year of tenure
- Private health insurance - including dental & optical
- £15/day lunch budget when working from our London office, up to £120/month
- £1,000 for your home office set up + £500/year top-up
- Annual team offsite to sunny spots (last ones were in Spain and Portugal ☀️)
- Join one of Europe’s fastest-growing startups
- Work with a veteran team of ex-employees of Google, Microsoft, Oracle, Coinbase, JP Morgan and more
- Health, fitness and gift card discounts
- Cycle2Work and Electric Cars scheme
- Hybrid work set up - typically 2 days in the office
- Ready to help us change the game for SaaS integrations? Get in touch and let's chat!
- We believe diversity drives innovation. We encourage individuals from all backgrounds to apply. As an equal-opportunity employer, we celebrate diversity and are committed to creating an inclusive environment for all employees.
Other
- StackOne is the AI Integration Gateway for SaaS products and AI Agents. Backed by GV and Workday Ventures ($24M raised), we help builders of SaaS platforms and AI Agents orchestrate hundreds of scalable, accurate, and enterprise-grade integrations. Our platform combines 25,000 pre-mapped actions on 200 connectors, an AI-powered integration development toolkit, plus security by design: a real-time architecture, managed authentication and permissions, and end-to-end observability.
- Join us on our fast trajectory to build the future of agentic integrations.
- StackOne’s product experience is our brand. As our first dedicated UX Engineer you will be the in-house authority on taste, polish, and performance. You will own the component library, shape our micro-frontend architecture, and ensure that every pixel, motion, and millisecond of latency makes customers feel like they’re using the best-engineered platform on the market.
- 80 % Front-end craft & design systems
- 20 % API-aware performance engineering
- Collaborate with our Designer to define & steward our design system – set the visual language, build reusable primitives, and maintain libraries that power every StackOne user interfaces.
- Ship pixel-perfect UIs – React (primarily) plus; own theming, performance, and thoughtful motion.
- Make performance a feature – instrument Core Web Vitals, budget bundle sizes, optimise hydration patterns, and chase performance where it matters.
- Provide and maintain internal tooling as well as AI rules to allow every technical team to contribute to the front-end while aligning with the best practices you will help set.
- Prototype & validate – turn product ideas into interactive proofs-of-concept that help PMs and designers converge on the right solution fast.
- Champion taste & detail – host design-quality critiques, stamp out visual debt, and be the go-to voice when “good enough” isn’t.