Founding Engineer (AI Start-up)

Most engineering roles hand you someone else's architecture, a backlog of legacy decisions and a ticket queue. This one hands you a blank-ish canvas, a working early product, and the job of deciding how it should be built over the coming years.

This early-stage, AI-native company is building agentic software: AI that works in the background on a user's behalf, pulling context from the tools they already use and acting on it. There's a product live with real users, a founder who has built and funded a tech company before, and a set of hard engineering problems that haven't been solved yet. That's where you come in.

We're looking for a Founding Engineer to own the technology end to end.

The engineering problems

• Agents in production: multi-step AI workflows that act autonomously and reliably, not chatbots
• Real-time and voice: low-latency conversational AI and live data flowing through the system
• Recommendation and ranking: matching logic that has to be accurate, explainable and get better with every interaction
• Integrations: connecting cleanly to email, calendars, messaging and third-party APIs
• Evals and guardrails: building the testing and evaluation layer that makes AI output trustworthy enough to act on

What you'll do

You'll own the architecture and technical roadmap, working directly with the CEO. You'll be hands-on most of the time: choosing the tools, setting the engineering standards, and shipping fast into the hands of real users. As the company grows, you'll hire and lead the team, shaping its culture.

What we're looking for

• Hands-on experience shipping LLM-powered products or agent workflows into production
• Strong full-stack TypeScript and React, with serverless and real-time cloud infrastructure
• A practical approach to AI evaluation, testing and reliability
• Someone who likes owning outcomes, making calls with incomplete information, and shipping quickly
• Bonus points for voice AI, ranking or recommendation systems, or previous founding-engineer experience

Why it's worth a look

• £100,000 base plus founding equity
• Greenfield where it counts, with the core engine still to be designed by you
• Your choice of tools and approach, with no legacy stack to inherit
• A short path from idea to production, with real users giving feedback quickly
• Work directly with an experienced, previously funded founder
• Hybrid working, London-based
• Build and lead the engineering team from day one