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 expertise in React and TypeScript.
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 UX Engineer in London employer: StackOne Technologies Limited
StackOne is an exceptional employer, offering a dynamic work environment where innovation thrives. As a Senior UX Engineer, you'll be part of a talented team dedicated to crafting top-tier user experiences while enjoying benefits like meaningful share options, generous holiday allowances, and a hybrid work setup. With opportunities for professional growth and a commitment to diversity, StackOne is the perfect place for those looking to make a significant impact in the tech industry.
Contact Details:
StackOne Technologies Limited Recruitment Team
StudySmarter Expert Advice🤫
We think this is how you could land Senior UX Engineer in London
✨Tip Number 1
Get your portfolio in tip-top shape! Make sure it showcases your best work, especially projects that highlight your skills in React and TypeScript. We want to see how you’ve tackled performance tuning and design systems, so don’t hold back!
✨Tip Number 2
Network like a pro! Reach out to current or former employees at StackOne on LinkedIn. A friendly chat can give you insider info about the company culture and maybe even a referral. We love seeing candidates who are genuinely interested in our mission!
✨Tip Number 3
Prepare for the technical interview by brushing up on your front-end engineering skills. Be ready to discuss your approach to building component libraries and optimising performance. We’re keen to hear your thought process, so practice explaining your decisions clearly.
✨Tip Number 4
Don’t forget to 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 UX Engineer in London
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 anything that highlights your attention to detail and UX design skills. A well-curated portfolio can really set you apart!
Tailor Your Application:Don’t just send a generic application! Take the time to tailor your CV and cover letter to reflect how your experience aligns with our needs at StackOne. Highlight your experience with React, TypeScript, and any design systems you've worked on.
Be Clear and Concise:When writing your application, keep it clear and to the point. We appreciate straightforward communication, so make sure your skills and experiences shine through without unnecessary fluff. Less is often more!
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 Technologies Limited
✨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.
✨Prepare for Technical Questions
Expect questions about front-end engineering and performance optimisation. Brush up on micro-frontend patterns and monorepo tooling. Practising coding challenges related to these topics can help you feel more confident during the technical part of the interview.
✨Be Ready to Collaborate
Since collaboration with designers is key, be prepared to discuss how you’ve worked with cross-functional teams in the past. Share examples of how you’ve contributed to design critiques or helped shape a design system. This will show that you value teamwork and can communicate effectively.
