Location: Norrköping / Stockholm, Sweden (CET)

Remote: Yes (EU/UK preferred); hybrid Stockholm OK

Willing to relocate: No

Technologies: React, TypeScript, Next.js, UI architecture/design systems, accessibility, performance profiling, realtime/event-driven UI (WebSockets), Playwright/Vitest, Node.js, SQL (Postgres/SQLite), Rust

Résumé/CV: https://www.kolibrinkpg.com/CV.pdf

Email: jonatan.wallgren@gmail.com

Senior frontend/product engineer focused on high-performance, tool-like interfaces for expert users. Strong on component architecture, accessibility, profiling-driven performance, and the “last 10%” polish (latency, UX sharpness, reliability) that keeps teams out of refactor holes. Comfortable owning frontend architecture end-to-end in small, high-agency teams; background includes realtime/concurrent UI systems and long-lived products where correctness matters. AI-assisted workflow when useful, gated by small diffs and tests so speed compounds rather than creating debt.