Lead Engineer – AI

Bjak; City Of London; On-site; GBP 70,000 - 100,000; Full time

Job summary

A self-funded AI group in the UK is seeking a Principal Engineer to lead the design and implementation of their AI systems. You will build core AI applications, optimize model quality, and mentor engineers. The ideal candidate has over 6 years of engineering experience, strong skills in machine learning, and is proficient in Python along with a backend language. This role is a unique opportunity to work on impactful projects in a high-performance team.

Qualifications

• Minimum 6 years of engineering experience required.
• Hands-on experience with machine learning is essential.
• Familiarity with production-level LLMs and RAG necessary.

Responsibilities

• Design and implement end-to-end AI systems.
• Build training, inference, and evaluation pipelines.
• Write production orchestration and feedback code.
• Optimize latency, cost, and model quality.
• Review PRs and mentor junior engineers.

Skills

Engineering experience

Machine Learning

Production LLM / RAG experience

Python

Backend development experience

Job description

A1 is a self-funded AI group, operating in full stealth. We’re building a new global consumer AI application where the intelligence layer is core to the product, not an add-on.

This is a founding technical leadership role. You will act as the principal builder of A1’s AI systems - writing production code, designing ML pipelines, and setting engineering standards while directly shaping how our AI works in the real world.

Why This Role Matters

• You define how AI systems are built at A1

• You connect data, models, evaluation, and product

• You raise the technical bar through direct contribution

What You’ll Do

• Design and implement end-to-end AI systems

• Build training, inference, and evaluation pipelines

• Write production orchestration and feedback code

• Optimize latency, cost, and model quality

• Review PRs and mentor engineers

Requirements

• 6+ years engineering experience

• Strong hands‑on ML background

• Production LLM / RAG experience

• Strong Python plus one backend language

Our Team & Culture

We operate as a dense, senior, high-performance team. We value clarity, speed, craftsmanship, and relentless ownership. We behave like founders — we build, ship, iterate, and hold ourselves to a high technical bar.

If you value excellence, enjoy building real systems, and want to be part of a small team creating something globally impactful, you’ll thrive here.

About A1

A1 is a self-funded, independent AI group, focused on building a new consumer AI product with global impact. We’re assembling a small, elite team of ML and engineering builders who want to work on meaningful, high-impact problems.