Fullstack Engineer (Founding)

We're building an AI travel agent for groups: your coolest, most helpful friend, inside an app. Hal, our agent, turns a vague idea into a real trip. Not a chatbot that hands you suggestions, but an agent that orchestrates tools across flight, stay, rail and ticket inventory, for a whole group at once, in a shared itinerary everyone is editing in real time.

You would turn ideas into shipped software, end to end, at a pace that surprises people. Schema to pixel, whatever the week needs. Nobody here will hand you a ticket.
What you will mostly do
Build the multiplayer, agentic layer travel has never had: a whole group editing one live plan while an AI books, rebooks and reasons on their behalf. Ship features end to end every week, from schema to edge function to UI to the analytics that tell you whether it worked. Meta-code, because most of our output goes through agents and you build the rules, commands and routines they run on. Know what could break before it does: migrations that must stay compatible with frozen TestFlight builds, RLS gaps, provider rate limits, AI spend per user. Pick your own work from what the product obviously needs.
Must have
Our stack, or close to it: React, TypeScript, Tailwind, Postgres, Supabase edge functions, with production experience across most of it. Mobile on iOS and Android, whether Capacitor or React Native, including store submissions, TestFlight, signing and release builds. You build with agents every day and know their failure modes and when to intervene. Speed to value: you pick up an unfamiliar API, domain or language and ship something real with it the same week.
Bonus
Consumer products, shipped to ordinary people at consumer quality bars. AI-native product work: LLM features in production, tool calling, streaming, evaluation, and the cost and latency mechanics that come with them. Multiplayer applications: realtime shared state, presence, conflict resolution.
Our stack
React, TypeScript, Vite, Supabase and Postgres, React Router, TanStack Query, Tailwind, Mapbox, Capacitor, Trigger.dev, PostHog, Sentry. We run Anthropic and Gemini side by side.
What you get
Salary calibrated to experience, in the range above. Equity, four-year vest with a one-year cliff. Hybrid in Stockholm. The ceiling on what you own is however much you can carry.

Full role description: https://halcy.site/careers/roles/fullstack-engineer