Sauna - Senior Frontend Engineer

• 4+ years of frontend engineering with a portfolio of complex web apps you've shipped — we want to see multiplayer experiences, apps handling large data with sophisticated fetching and caching, or work with server-sent events (SSE). • You love React and deeply understand state management. You know when to useMemo, how callbacks work, the component lifecycle, and you write beautiful, reusable components. You recognise when props are being drilled through multiple layers and should be lifted into context or Zustand instead. • You're comfortable owning a feature full-stack. You can do the DB migration, write the route in the backend, fetch on the frontend, and create the UI for it. • Product sense and design intuition — you can take a rough product direction, sketch an interaction, and ship something that feels right. • You care about performance. You know when to cache, when to refetch stale data, and how to optimistically update the UI. You notice duplicated network requests. You care about the app feeling snappy and responsive. • You make design decisions — you'll need to own some UX decisions, create simple designs when needed, and unblock yourself. • High autonomy, low ego — you don't wait for permission or perfect specs. You ship, gather feedback, and iterate. • You care about craft — details like loading states, empty states, error messages, keyboard shortcuts. The 1000 small decisions that make software feel good. • Experience with multiplayer apps (Y.js, Automerge, CRDTs, or similar real-time collaboration frameworks). • Built interfaces for LLM-based tools (streaming responses, handling uncertainty, progressive disclosure). • Experience with local-first architectures (IndexedDB, service workers, sync strategies). • Design background or strong visual sense — you can make things look good without a designer. • Been a founding frontend engineer and established standards from scratch.