Founding Engineer (Travel Product)

We are a fast-scaling travel startup with strong product-market fit ($1.46M ARR and growing) building Marlow AI — an AI-assisted trip planning experience that hands off to a real human advisor to lock in the details and book the trip accurately. We are two-sided: travelers get a consumer product that plans and books real trips, and advisors get a SaaS-style subscription with certification and qualified leads baked into the offer.

Currently, we are looking for a Founding Engineer — someone who can own features end-to-end, from database schema through the server function layer, the UI, and the tracking that tells us whether it worked, and ship them without needing a hand-off. This is one of the first technical hires on the team: your fingerprints will be on the architecture, the integrations, and the decisions that shape how we scale from here.

• Own features end-to-end: schema design  server function  UI/UX  event tracking  ship to production, using our stack of React 19, TanStack Start, Supabase (Postgres + RLS), and Cloudflare Workers
• Work directly in the Marlow AI trip-planning flow and the advisor handoff/booking flow, across both the traveler-facing and advisor-facing surfaces
• Design and evolve Postgres schemas with Supabase, including RLS policies and GRANTs that actually hold up under real traffic
• Integrate and maintain third-party APIs  flights (Kiwi Tequila), hotels (Hotelston SOAP), payments (Primer, PayPal Marketplace), subscriptions/leads (Kilo Launchpad)  including auth, webhooks, and signature verification
• Build and refine LLM-powered tooling inside Marlows orchestration layer (tool-calling, streaming, prompt iteration) across OpenAI, Anthropic, and OpenRouter
• Instrument features against our unified event schema (view_item, add_to_cart, initiate_checkout, add_payment_info, payment_complete) so product and growth decisions are backed by real data
• Ship on Cloudflares edge runtime and reason clearly about SSR vs. client boundaries in TanStack Start
• Write tests where they earn their keep, and work alongside AI-agent dogfooding
• Take ownership of ambiguous problems, make a call, and move  this is a one-engineer-per-feature environment, not a hand-off pipeline
• Help shape technical direction as we grow  you wont be handed a spec and a backlog forever; as the team grows, expect a voice in architecture calls and, over time, a hand in shaping the engineering team itself

• Have 3 6 years shipping production web apps, including at least one seed / Series A or B startup as an early hire (employee #2 15)
• Be comfortable being the only engineer on a feature, from DB migration to UI/UX, with no one else to lean on
• Have personally shipped something using Supabase, Postgres RLS, or pgvector  and understand why RLS-plus-GRANT is non-negotiable, not optional hardening
• Be TypeScript-native: you write it and read it without flinching, not Ive used TS before
• Have hands-on experience with at least one meta-framework (Next.js, Remix, TanStack Start, SvelteKit) and understand SSR vs. client boundaries
• Have integrated at least 10 third-party APIs, including auth, webhooks, and signature verification  payment processors, comms platforms, legacy SOAP vendors, or similar
• Have strong communication skills and be comfortable working directly with founders and cross-functional stakeholders

Nice to have

• LLM tool-calling experience: function calling, streaming, prompt versioning
• Experience on edge/Workers runtimes
• SQL beyond CRUD: window functions, CTEs, triggers
• Exposure to supervised fine-tuning for AI

• Own your wellness Stay sharp and well in your own way  health insurance (after probation), on-site physiotherapist, office gym, and fitness classes keep you moving. Plus 7 extra days off, 3 for weddings, hybrid work, and the freedom to work 2 months from anywhere in the world.
• Boost your daily life Every breakthrough needs a spark and our daily setup reflects that. Pet-friendly office, fresh breakfasts, hot lunches, drawers and fridges stocked with snacks and food  for a quick bite or even a team-cooked meal together. Rooftop and cellar events keep things lively, while 10 social clubs give space to dive into passions and try new things. Add a public transport card for Vilnius and Perks.lt perks for smoother days.
• Shape your growth path Builders never stop learning. Coaching, mentorship, training, conferences, online courses, subscriptions, books  youve got a 200 yearly budget to fuel personal or team growth. You pick the path  well back you all the way.
• Drive global impact This is where ambition scales. Build impact across 30+ brands worldwide. Launch bold projects. Even step in as a co-founder  we reward those who push further. And if you bring in more great people, you get 1500 for every successful referral.