Lead Backend AI Engineer - Developer Platform

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

Benefits offered by this job

Equity participation

Job summary

Healf is seeking a Founding AI Engineer on the Developer Platform team to build foundational platform systems—identity, authentication, authorization—and other critical infrastructure services.

You will design and build AI-powered agents and developer tooling to accelerate software development, including AI-assisted coding, automated QA, and incident monitoring. You will shape the technical architecture and drive engineering excellence with potential to lead a small team.

Qualifications

• Hands-on experience building core platform systems (Identity, Authentication, Authorization).
• Experience developing AI agents and automation for engineering workflows.
• Strong backend engineering with Python and AWS; scalable design.

Responsibilities

• Architect and build core platform services used across engineering teams.
• Develop AI agents and developer tooling to accelerate coding and QA.
• Own core infrastructure, ensuring scalability, reliability, and cost optimization.
• Define architectural decisions across stack, deployment, and data systems.
• Mentor junior engineers and establish engineering best practices.

Skills

Identity & Auth

Python

AWS

AI agents

Mentoring

CI/CD

Tools

LangGraph

LangChain

Job description

About The Role

Healf is Europe's fastest-growing health and wellness company — number one on the FT1000 and Sifted 100. We have gone from £1m to over £100m in under three years, and we are building the technology platform that takes us to £1bn. That means every engineering decision made now shapes what is possible for tens of millions of people.

As our Founding AI Engineer on the Developer Platform team, you will build the foundational platform systems that drive engineering quality, reliability, and velocity across the organization. You will own the development of core platform capabilities, including identity, authentication, authorization, and other critical infrastructure services.

In addition, you will design and build AI‑powered agents and developer tooling to accelerate software development and improve quality—ranging from AI‑assisted coding and automated QA to incident detection, monitoring, and operational workflows. Your work will enable engineers to move faster while maintaining high standards of reliability and performance.

You will define the technical architecture, make key infrastructure and platform decisions, and play a central role in shaping our engineering foundations. Over time, you will have the opportunity to build and lead a small team around this function.

This is a true 0‑to‑1 role with significant ownership, direct partnership with the CTO, and meaningful equity participation.

What You Will Do

• Architect and Build: Core platform services including Identity, Authentication, Authorization, and other foundational backend systems used across engineering teams.
• AI Agents / Harnesses: Build AI agents and developer productivity tooling to accelerate coding, automate bug fixing through Slack and Linear, enable AI‑powered QA testing, and drive intelligent incident monitoring and resolution.
• Own: The core engineering infrastructure, ensuring scalability, reliability, security, and ongoing cost optimization.
• Set the Technical Foundation: Define key architectural decisions across the technology stack, deployment model, platform architecture, and data systems.
• Lead / Mentor: Mentor junior engineers and help establish engineering best practices, technical excellence, and a high‑performance culture.

What We Are Looking For

• Hands‑on experience building and operating core platform systems such as Identity, Authentication, Authorization, and shared backend infrastructure.
• Hands‑on experience developing AI agents and automation systems for engineering workflows including coding, debugging, testing, incident management, and developer productivity.
• Strong architecture instincts; able to quickly reason through complex system design problems and make sound technical trade‑offs.
• Strong backend engineering experience with AWS and excellent proficiency in Python.
• Experience with AI orchestration frameworks and tooling such as LangGraph, LangChain, or similar agent‑based development frameworks.
• Experience building and maintaining CI/CD pipelines, automated testing infrastructure, and modern software delivery systems at scale.
• Comfortable balancing deep individual contributor work with mentoring and supporting other engineers.

Nice to Have

• Experience at a developer tooling, infrastructure, platform, or AI‑first company.
• Experience building internal developer platforms or engineering productivity systems.

The Deal

Competitive and meaningful compensation package for the right person. We ask a great deal of the people who work here. We expect full ownership and a genuine commitment to give this chapter everything you have. In return, we will give you the same: everything we have, invested in your growth, your wellbeing, and the defining skills of the next decade. We have built the fastest‑growing company in Europe with a team small enough that every person in it shapes the outcome. That is still true today. The next person we hire will change the trajectory of the company. If the most important work of your career is ahead of you, this is the place to do it.