Full Stack Product Engineer

We're working with a YC-backed startup building AI agents that don't just answer customer support tickets, they actually resolve them. Their agents cancel orders, issue refunds, update subscriptions, check inventory, talk to warehouse systems and suppliers, and continuously improve over time. Sitting above them is an AI Manager, a product that enables support teams to train, monitor and improve AI agents without needing engineers or writing prompts. They're now hiring their second engineer in the founding team, looking for a strong fullstack product engineer to work directly alongside the founders. This is a genuinely founding-level opportunity. You'll have a huge influence over both the product and engineering culture as they build towards making AI-powered customer support entirely self-serve. What you'll be working on The biggest challenge isn't building another AI agent. It's making incredibly sophisticated AI feel intuitive, reliable and genuinely useful.You'll own features end-to-end, working across the frontend and backend to turn ideas into polished, production-ready experiences.You'll work closely with the founders to prototype, iterate and ship quickly. From building onboarding experiences and workflow builders, to designing backend services and APIs, visualising agent behaviour and creating new ways for merchants to configure and improve their AI workforce, you'll help define how customers interact with the product.You'll be comfortable moving across the stack, from building intuitive product experiences in React and TypeScript to designing backend services, APIs, data models and integrations in Python.You'll need to understand the systems underneath the interface and be comfortable taking ownership of a feature all the way from the initial idea through to production.AI is fundamental to how the team designs, builds and ships software every day. They're looking for someone who embraces AI-first development as a force multiplier, not a shortcut. What they're looking for Someone who's built real products and loves owning problems from idea through to production.You're a strong fullstack engineer, comfortable with React, TypeScript and modern frontend engineering, alongside solid backend experience.You're confident designing APIs, working with databases and backend services, thinking about architecture and infrastructure, and contributing across the stack.You have strong product instincts and a great eye for UX. You naturally spot friction, care about the details and enjoy turning complex systems into beautifully simple experiences.You enjoy working across the stack rather than being constrained to one layer. You're happy going deep into backend logic one day and obsessing over a tiny interaction or product detail the next.You're resourceful, curious, thrive in ambiguity and are excited by the opportunity to help shape a company from the earliest days alongside the founders.You're excited by AI-native product development and interested in how software and engineering workflows change when AI becomes a fundamental part of the stack. The stack TypeScript, React and Next.js on the frontend. Python and FastAPI on the backend. AWS, Vercel, Neon, Terraform, plus an in-house AI runtime. The team is based in Amsterdam. If you want to help define how humans work alongside AI agents, own product features end-to-end and build both the product and technology from the ground up, we'd love to hear from you.