Lead Backend Engineer

Salary: £49,000 - 89,000 per year

Requirements

• We are looking for a truly world-class engineer who has seen what great looks like and can take ownership to build the foundations for a global agentic marketplace.
• You are a systems thinker first, understanding how the parts interact, where failure hides, and what breaks at ten times the volume.
• You have architected real systems end to end, more than once, and run them in production at the scale of millions of users.
• You take the edges seriously, including retries, idempotency, backpressure, and duplicate messages.
• You are AI-native at the frontier and help set the practice for the team, from planning to evals.
• You are strong in TypeScript and productive in whatever a problem needs within days.
• You are happiest thinking out loud with the team.
• UK right to work is required.
• Bonus points if you have led a team or worked in UK property or utilities.
• Bonus points if you have moved house in the UK and understand the problem firsthand.

Responsibilities

• We architect the platform that runs home life.
• We design the architecture for households, properties, partners, suppliers, and how they relate.
• We build state machines that every order runs on, clear enough for an agent to act on.
• We define contracts between domains, data, queues, and infrastructure.
• We design for speed and reliability, including sub-second reads for live voice.
• We ship observability with the feature, rehearse rollbacks every release, and make small changes to production daily.
• We move live systems onto a modern stack without dropping anything.
• We make agents first‑class customers with permissioned access to read and act, idempotency, audit trails, and controls around money.
• We use config over code so commercial teams can change pricing without a deploy.
• We own the outcome end to end and clear whatever stands between us and it.
• We raise the standard across the team and help make work more joyful.
• We set the engineering practice from planning to evals.

Technologies

• AI
• API
• AWS
• Architect
• Backend
• Claude Code
• FastAPI
• Python
• TypeScript
• Cloud

More

We are building Jay, a personal AI that takes the admin out of moving and home life, then keeps the household running by setting up and managing services such as energy, broadband, water, council tax, insurance, renewals, and deals. We plug into the property industry and hundreds of suppliers, with one entity model and one API that turn a move into services set up, switched, and paid for. We are UK first, then global, operating in a $1T home services market with 4M home movers a year in the UK and 28M UK households to serve. We are a B Corp and FCA regulated, and we care deeply about customers, reflected in 4.9 ratings on Trustpilot and Google. The stack includes TypeScript on the backend, Python and FastAPI for Jay, Next.js up front, AWS underneath, and Claude Code woven through how we build. We are based in London, with a few days a week in the office. Compensation includes competitive cash plus equity, and we work hard with generally strong work‑life balance. The role reports to the Head of AI and Engineering.

last updated 40 week of 2026

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