Senior Software Engineer, UI Platform

Project overview

Our client’s platform is already trusted by Fortune 500 companies and fast-growing startups, and now it’s becoming the data layer that lets enterprises run AI agents safely in production. It combines streaming, SQL and connectivity with a governance layer that controls what agents can see and do, and keeps a tamper-proof record of everything they touch.

You’ll join their growing Warsaw office as a hands-on engineer building the shared UI platform behind their cloud product. This isn’t a typical frontend role: the team wants a strong engineer with a real UX mindset, someone who cares as much about how the product feels as about how it’s built. You’ll work with frontend and backend engineers across Europe and the Americas, alongside the team that owns sign-up, billing and payments.

• Move product surfaces into independently deployable microfrontends (Module Federation).
• Build data-rich, customer-facing UIs end to end, from design review to production.
• Keep the UI usable when one part fails, with graceful fallbacks.
• Own testing from unit to end-to-end, keeping tests fast and reliable.
• Shape the design system and component library, including for AI coding agents.
• Write RFCs and review designs and code.
• Work with backend engineers so APIs and UX fit together.
• Join the on-call rotation for cloud services.
• Mentor teammates through pairing and code review.
• 5+ years building production web apps with React and TypeScript.
• A strong eye for UX and design: you notice when something feels off.
• Experience with design systems and component libraries.
• Microfrontend experience (Module Federation, single-spa or similar).
• Solid frontend fundamentals: state, data fetching, performance, accessibility.
• Confident testing from unit to end-to-end.
• Daily use of AI coding tools (Claude Code, Cursor, Copilot).
• Ownership of projects from design to production with little guidance.
• Fluent English and comfort working async with a distributed team.

Project details

• Start: ASAP
• Location: Warsaw, PL