Founding Engineer (up to £120k)

Dex; Greater London; On-site; GBP 120,000 - 160,000; Full time

Job summary

Dex is partnering with a pioneering startup to build a compliance layer for regulated infrastructure. As Founding Engineer you will own end-to-end problems, influence architecture and product decisions, and work closely with the CTO and ML/Platform leaders.

You will lead Python backend development using FastAPI, design the PostgreSQL data layer, drive CI/CD and Azure deployments, and contribute to the React frontend when needed. Occasional travel to Cambridge is expected.

Qualifications

• Strong Python backend experience with production-grade systems.
• Experience with large language models in real systems.
• Willing to travel to the Cambridge office once a week.

Responsibilities

• Build agentic AI workflows in production.
• Lead backend development in Python and FastAPI.
• Architect the PostgreSQL data layer.
• Drive CI/CD and Azure deployments.
• Contribute to the React frontend when needed.

Skills

Python

Backend development

Domain-driven design

Event-driven architecture

AI tooling

Tools

FastAPI

PostgreSQL

Azure

CI/CD

React

Job description

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process.

Dex is an AI recruiter agent that helps you run your job search. Tell Dex your stack, seniority, and what you want to build. We will manage your applications and surface other opportunities that are a fit.

This company is building the compliance layer for regulated infrastructure, starting with critical national assets like the NHS estate. They are solving a genuinely hard problem: bringing search, evidence, workflow, and assurance into one platform for sectors where safety and regulatory adherence are paramount. With paying customers and strong traction, they are rapidly expanding their impact.

As a Founding Engineer, you'll be the senior addition to a small, high-calibre engineering team, working alongside the CTO and Head of ML & Platform. This isn't a role where you'll be handed detailed specs; you'll own problems end-to-end, from understanding user needs to designing and shipping solutions. You'll make architectural decisions that directly impact the product, not just implement them.

The work

• Build agentic AI workflows that hold up in production.
• Lead backend development in Python and FastAPI.
• Architect the PostgreSQL data layer.
• Drive CI/CD and Azure deployments.
• Contribute to the React frontend when needed.

What You Bring

• You've owned an area of responsibility back-to-front at a startup, taking customer requirements through to production code, without needing to have managed anyone.
• You're strong in Python backend work and think in domain-driven design, clean architecture, and event-driven patterns.
• You've built with large language models in real systems that shipped, not just experimented with them.
• You use AI coding tools as a normal part of how you work, and you're pushing on what they can do.
• You're comfortable travelling to the Cambridge office once a week to sync with the rest of the engineering team.