Full-Stack Engineer

Lexerus is an early-stage retail-tech company building AI-powered loss prevention for UK supermarkets and independent retailers.

Our platform watches live camera feeds and flags shoplifting as it happens — not hours later in a review queue. Detection runs on-device in the store, so footage never leaves the premises unless a retailer chooses to keep it as evidence.

We're deployed in live stores today, and we're scaling the product, the detection models, and the team.

The Impact You’ll Make

As a Full-Stack Engineer at Lexerus, you'll build the surfaces people actually touch — the mobile app a shop manager checks mid-shift, the in-store desktop app, and the API that ties them together.

You'll take features end-to-end: from a conversation with a store manager, through the backend and the UI, to something running in a live shop. Our products have to be legible to someone who is mid-shift, holding stock in one hand, and has no patience for a confusing interface.

This is a role for someone who likes owning whole features and cares about the last 10% — the empty states, the offline case, the alert that arrives at 2am.

What You’ll Do

• Lead features end-to-end, from design through to deployment, across mobile, desktop, and the API.
• Build and maintain the React Native (Expo) mobile app that store staff use to triage alerts.
• Work on the Tauri desktop app that runs in-store, including its local detection sidecar and sync workers.
• Design and build FastAPI endpoints and PostgreSQL schemas that hold up as we add stores.
• Turn detection output into interfaces a busy shop manager can act on in seconds.
• Own production-readiness: observability, error handling, and the failure modes that only show up in a real store.

Who You Are

• 3-5 years of full-stack engineering experience.
• Strong skills in React, TypeScript, and modern front-end practice.
• Backend experience with Python (FastAPI) and PostgreSQL, or close equivalents, plus sound judgement on system design.
• Comfortable using AI-powered development tools to move faster, without letting code quality slip.
• Thoughtful and fast-moving, with a proactive, product-oriented mindset and a bias for action.
• Interested in building software with consequences attached.

Bonus Points For

• Experience with React Native or Expo in production, including app store releases and OTA updates.
• Worked with Tauri, Electron, or other desktop application frameworks.
• Familiarity with real-time systems — WebSockets, streaming, or video.
• Experience with Stripe billing, subscriptions, and multi-tenant data models.
• Prior startup or 0→1 experience.

Why Lexerus

Real-world impact: UK retailers lose £4.2bn a year to theft. The people you're building for are shop staff who have largely stopped reporting it because nothing happens when they do.

Hard problems, real constraints: Real-time computer vision on modest in-store hardware, running all day, with false positives that cost a retailer their trust. There is nowhere to hide a sloppy system.

Ownership from day one: We're a small team. You'll own whole surfaces of the product, make the technical calls on them, and see your work running in a store the same week.

Short feedback loops: We talk to the shop managers using Lexerus directly. Feedback arrives in days, not quarters, and it shapes what we build next.

Early-stage opportunity: Competitive salary, flexible remote working across the UK, and meaningful equity for early team members.