At a Glance
- Tasks: Craft stunning UIs and optimise performance for a cutting-edge integration platform.
- Company: Join StackOne, a fast-growing startup backed by top investors.
- Benefits: Enjoy meaningful share options, private health insurance, and a generous holiday allowance.
- Other info: Work with a talented team from Google, Microsoft, and more in a hybrid setup.
- Why this job: Be the first dedicated UX Engineer and shape the future of agentic integrations.
- Qualifications: 4+ years in front-end engineering with React and TypeScript expertise.
The predicted salary is between 60000 - 80000 £ per year.
About StackOne: 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.
Why this role exists: 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.
What you’ll do:
- 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 interface. 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.
What you’ll bring:
Must-haves:- 4+ yrs professional front-end engineering with a portfolio that focuses 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 performance bottlenecks, instrument metrics, or adjust API shape.
- 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.
Why Join Us?
- 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
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.
Senior UI Engineer employer: StackOne
StackOne is an exceptional employer, offering a dynamic work culture that fosters innovation and collaboration among a team of seasoned professionals from top tech companies. With meaningful share options, generous holiday allowances, and a commitment to employee well-being through private health insurance and a robust home office setup, StackOne prioritises the growth and satisfaction of its employees. Join us in our London office for a hybrid work experience that balances flexibility with engaging team activities, all while contributing to the future of AI integrations.
StudySmarter Expert Advice🤫
We think this is how you could land Senior UI Engineer
✨Tip Number 1
Get your portfolio in tip-top shape! Make sure it showcases your best work, especially those pixel-perfect UIs and design systems you've crafted. We want to see your attention to detail and how you’ve tackled performance challenges.
✨Tip Number 2
Network like a pro! Connect with folks in the industry on LinkedIn or at meetups. We’re all about collaboration, so don’t hesitate to reach out to current StackOne employees or others in the field to get insights and maybe even a referral.
✨Tip Number 3
Prepare for the interview by brushing up on your React and TypeScript skills. We love seeing candidates who can dive into back-end code too, so be ready to discuss how you’ve optimised performance and tackled any bottlenecks in your projects.
✨Tip Number 4
Apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we love candidates who take the initiative to engage directly with us. Let’s build the future of agentic integrations together!
We think you need these skills to ace Senior UI Engineer
Some tips for your application 🫡
Show Off Your Portfolio:Make sure to include a link to your portfolio in your application. We want to see your best work, especially projects that highlight your attention to detail and your experience with React and TypeScript.
Tailor Your Application:Don’t just send a generic application! Take the time to tailor your CV and cover letter to reflect how your skills align with our needs at StackOne. Highlight your experience with design systems and performance tuning.
Be Clear and Concise:When writing your application, keep it clear and to the point. We appreciate straightforward communication, so make sure your passion for UI engineering shines through without unnecessary fluff.
Apply Through Our Website:We encourage you to apply directly through our website. It’s the best way for us to receive your application and ensures you’re considered for the role. Plus, it shows you’re keen on joining our team!
How to prepare for a job interview at StackOne
✨Know Your Stuff
Make sure you’re well-versed in React, TypeScript, and CSS. Brush up on your knowledge of performance tuning tools like Lighthouse and Core Web Vitals. Being able to discuss your past projects and how you’ve tackled performance issues will show that you’re the right fit for StackOne.
✨Showcase Your Portfolio
Bring along a portfolio that highlights your best work, especially any component libraries or design systems you've built. Be ready to explain your design choices and how they contribute to user experience. This is your chance to demonstrate your attention to detail and craftsmanship.
✨Collaborate and Communicate
Since this role involves working closely with designers, practice discussing design concepts and how you can contribute to the visual language of StackOne. Be prepared to share your thoughts on design critiques and how you can help maintain high standards in UI quality.
✨Ask Insightful Questions
Prepare some thoughtful questions about StackOne’s product vision and how the UX Engineer role fits into that. Inquire about their current design system and performance goals. This shows your genuine interest in the company and helps you understand if it’s the right place for you.
