Founding Product Engineer Job at London, England, United Kingdom Full Time

A Y Combinator-backed AI SaaS startup is looking for a Founding Product Engineer to join at the earliest stage. You’ll work directly alongside the founders to build core product features, shape architecture, and own outcomes from day one. This role blends hands-on full-stack engineering with strong product judgment, design sensibility, and a modern AI-augmented workflow. If you thrive at founder speed, love talking to users, and want to leave a real mark on a product, this is the role.

What You’ll Do

• Build and ship core product features end-to-end with high autonomy.
• Collaborate tightly with the founders day-to-day in a fast-paced, high-trust environment.
• Leverage AI tools (e.g., Cursor, Claude Code, Codex, agent workflows) as a core part of your daily development process.
• Talk to users constantly — identify bottlenecks, iterate quickly, and ship fixes.
• Propose and prototype new features, products, and internal tooling.
• Help define engineering standards, architecture decisions, and team pacing.
• Take deep ownership of projects from conception through completion.

What We’re Looking For

Required:

• 1–5 years shipping real product software (full-stack) with genuine ownership.
• Strong TypeScript and React skills; comfortable building full-stack features independently.
• Heavy, genuine use of AI coding tools as part of your everyday workflow.
• Strong product instincts and good design taste; Figma fluency is a plus.
• High agency — you notice problems, propose solutions, and drive them to completion.
• Comfort with ambiguity and operating at founder speed in an early-stage environment.
• Clear communication and strong judgment.

Nice to Have:

• Experience building devtools, sandboxed systems, or safety-sensitive products.
• Familiarity with real-time or collaborative systems (e.g., Cloudflare Workers, Durable Objects, service bindings).
• Background at a fast-moving startup or high-output product team.

Location

This role is based on-site in London, England, United Kingdom. Visa sponsorship is not available.

Compensation & Benefits

Competitive salary and meaningful early-stage equity. Exact compensation will be discussed during the interview process.