Full Stack AI Engineer

Full Stack AI Engineer: Build AI Agents Used by Fortune 100 Companies Are you the sort of engineer who loves shipping product end-to-end? Do you want to work in a tiny team where your code reaches production immediately, your ideas shape the roadmap, and AI isn't a feature—it's the entire product? A YC-backed startup in San Francisco has just signed its first seven-figure enterprise customer and is now scaling quickly. With only five people on the team, they're already building AI agents used by Fortune 100 companies to automate complex business workflows that previously took days or even weeks. They're looking for a Mid or Senior Full Stack AI Engineer who enjoys building products from scratch, moving quickly, and taking ownership across the entire stack. What You'll Do: 🤖 Build AI Products – Design and ship AI agents that automate complex enterprise workflows, integrating LLMs into real production systems. ⚡ Own the Product – Build features end-to-end across React, Next.js, TypeScript and backend services, taking ideas from customer conversations through to production. 🏗 Solve Real Engineering Problems – Build secure, scalable enterprise software, integrating with systems like SAP while supporting GDPR-compliant deployments across Europe. 🚀 Shape the Company – Join a five-person engineering team where you'll help define both the product and engineering culture as the company scales. What They're Looking For: ✔ 3+ years building production software, ideally in startups or high-growth product companies. ✔ Strong full stack engineering skills, particularly with TypeScript, React and modern backend development. ✔ Comfortable using AI coding tools such as Cursor, Claude Code or Copilot as part of your daily workflow. ✔ Product-minded engineers who enjoy ambiguity, talking to customers and owning features from idea to launch. ✔ Excited by startups, fast iteration and working directly alongside founders. Why Join? 💰 $180,000–$230,000 base (up to $250k for exceptional candidates) 📈 0.5–1.25% equity 🏢 Five days per week in their San Francisco office, working alongside a small, highly ambitious team. 🚀 Backed by Y Combinator and leading venture investors, with real enterprise traction already secured and demand growing rapidly. This isn't a role maintaining existing software. It's an opportunity to build AI products from the ground up at a company that's already proving customers will pay for what they're building.