At a Glance
- Tasks: Craft stunning UIs and optimise performance for our cutting-edge SaaS platform.
- Company: Join StackOne, a fast-growing startup backed by top investors.
- Benefits: Enjoy competitive salary, share options, health insurance, and generous holiday.
- Other info: Collaborate with a veteran team and enjoy hybrid work flexibility.
- Why this job: Be the first dedicated UX Engineer and shape the future of integrations.
- Qualifications: 4+ years in front-end engineering with React and TypeScript expertise.
The predicted salary is between 43200 - 72000 € 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 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.
- 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
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.
Senior UX Engineer employer: StackOne
At StackOne, we pride ourselves on being a forward-thinking employer that values innovation and creativity. As a Senior UX Engineer, you'll be part of a dynamic team that fosters collaboration and personal growth, with access to meaningful share options, generous holiday allowances, and a hybrid work setup that promotes work-life balance. Our vibrant London office offers a supportive environment where your contributions directly impact the future of SaaS integrations, all while enjoying perks like private health insurance and annual team offsites to exciting locations.
StudySmarter Expert Advice🤫
We think this is how you could land Senior UX Engineer
✨Tip Number 1
Network like a pro! Reach out to folks in the industry, attend meetups, and connect with StackOne employees on LinkedIn. A personal touch can make all the difference when it comes to landing that interview.
✨Tip Number 2
Show off your skills! Create a portfolio that highlights your best work, especially projects that showcase your front-end engineering prowess. Make sure to include examples of your React and TypeScript projects to catch our eye.
✨Tip Number 3
Prepare for the interview by brushing up on performance tuning and design systems. We love candidates who can discuss their thought process and how they approach challenges, so be ready to share your insights!
✨Tip Number 4
Apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we’re always on the lookout for passionate individuals who want to help us build the future of agentic integrations.
We think you need these skills to ace Senior UX 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 UX design skills. This is your chance to shine!
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. Highlight your expertise in React, TypeScript, and performance tuning – we love specifics!
Be Authentic:Let your personality come through in your writing. We’re looking for someone who’s not just skilled but also a great fit for our team culture. Share your passion for UX and why you’re excited about this role at StackOne!
Apply Through Our Website:We encourage you to apply directly through our website. It’s the easiest way for us to keep track of your application and ensures you don’t miss out on any important updates. Let’s get started on this journey together!
How to prepare for a job interview at StackOne
✨Know Your Stuff
Make sure you brush up on your React and TypeScript skills before the interview. Be ready to discuss your past projects in detail, especially those that showcase your attention to detail and performance tuning instincts.
✨Showcase Your Portfolio
Bring along a portfolio that highlights your best work, particularly any component libraries or design systems you've built. Be prepared to explain your design choices and how they contribute to user experience.
✨Understand Performance Metrics
Familiarise yourself with Core Web Vitals and other performance metrics. During the interview, be ready to discuss how you've optimised performance in previous projects and how you would approach it at StackOne.
✨Ask Insightful Questions
Prepare thoughtful questions about StackOne's design system and micro-frontend architecture. This shows your genuine interest in the role and helps you understand how you can contribute to their mission of building top-notch integrations.
