Full Stack Developer - UX (EU)

You'll own the UX and much of the application logic for a highly interactive, spreadsheet-style table. Your north star is speed, polish, and correctness the experience should feel as smooth as the best modern tools (Notion, Google Sheets, Clay). What you'll do Build a virtualized, configurable table that performs smoothly at scale (50k100k+ rows) with features like resize/reorder, hide/show, freeze, multi-select, bulk edit, and inline validation. Deliver a rich filter and sort experience: multi-field, AND/OR groups, saved views, quick search, and faceting powered by a search backend. Implement inline editing with optimistic updates, conflict resolution, and resilient fallbacks (e.g., retry queues). Create advanced column operations: duplicate/rename, derived or computed fields, enrichment triggers per row/selection. Maintain high UX standards, including empty/error/loading states, responsive layouts, and internationalization readiness. Continuously instrument and optimize performance (virtual scrolling, memoization, batching) to meet TTI/LCP budgets, p95 latency goals, and fps targets while scrolling. You may be a fit if you have 5+ years of experience building production React + JavaScript applications, with deep knowledge of state management. Hands-on work with complex grid/table UIs (TanStack Table, ag-Grid, Handsontable, or custom solutions). Strong understanding of rendering performance (virtualization, windowing, event batching) and core web fundamentals (layout, paint, compositing). Comfort working with Node.js APIs (REST), Postgres, and Elasticsearch. A strong product sense: you care about edge cases, usability, and discoverability. Nice to have Experience with real-time collaboration (Yjs, Automerge, Liveblocks, WebSockets). File handling expertise: import/export (CSV/Parquet), bulk operations, clipboard integration. Familiarity with design systems (Radix, Headless UI), accessibility audits, and visual regression testing. Knowledge of feature flags, product analytics (PostHog/Amplitude), and error monitoring tools.