Senior Frontend Engineer

Sauna•San Francisco, CA

4d•$180,000 - $240,000•Onsite

About The Position

This is a full-time, in-person role based in San Francisco (Presidio) - we work from the office 5 days a week. You must be based in the Bay Area or willing to relocate before starting. We require US work authorisation, but are open to O-1 or J-1 visa sponsorship for exceptional candidates. About Sauna by Wordware: Most AI products hand you a coworker on day one and hope you trust it. Sauna is the coworker you raise: it starts by learning how you work, earns autonomy task by task, and ends up running hours of work on its own while you keep taste, review, and the final say. Wordware is the ~20-person team behind it, backed by Spark Capital, Felicis, and Y Combinator with a $30M seed, the largest in YC history. We build from a San Francisco office in the shadow of the Golden Gate Bridge, and we work absurdly hard because we can see and feel the outcome every day. About the Role: You'll own the frontend of Sauna: shipping interfaces that feel instant, intuitive, and polished even when the underlying work is complex.

Requirements

Minimum: 4+ years of frontend engineering with a portfolio of complex web apps you've shipped.
Portfolio should include multiplayer experiences, apps handling large data with sophisticated fetching and caching, or work with server-sent events (SSE).
Love React and deeply understand state management.
Know when to useMemo, how callbacks work, the component lifecycle, and write beautiful, reusable components.
Recognize when props are being drilled through multiple layers and should be lifted into context or Zustand instead.
Comfortable owning a full-stack feature.
Product sense and design intuition: you can take a rough product direction, sketch an interaction, and ship something that feels right.
Care about performance.
Know when to cache, when to refetch stale data, and how to optimistically update the UI.
Notice duplicated network requests.
Care about the app feeling snappy and responsive.
High autonomy, low ego: you don't wait for permission or perfect specs.
Care about craft: details like loading states, empty states, error messages, keyboard shortcuts. The 1000 small decisions that make software feel good.
US work authorisation.

Nice To Haves

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.

Responsibilities

Make product and design calls yourself.
Prototype quickly.
Execute without waiting for perfect specs.
Implement designs.
Create designs.
Own the frontend of Sauna: shipping interfaces that feel instant, intuitive, and polished even when the underlying work is complex.
Do the DB migration, write the route in the backend, fetch on the frontend, and create the UI for it.
Own some UX decisions, create simple designs when needed, and unblock yourself.
Ship, gather feedback, and iterate.
Focus on details like loading states, empty states, error messages, and keyboard shortcuts.