Principal ML Engineer

About the role

We are partnering with a well‑funded, stealth AI startup that is building a next‑generation AI assistant to help users manage everyday tasks, conversations and workflows. The product is pre‑launch, offering a rare opportunity to join a small, high‑calibre engineering team and shape the machine‑learning systems from day one.

Key responsibilities

• Design, build and deploy production‑grade machine‑learning systems.
• Own the full ML lifecycle, from data preparation through training, evaluation and inference.
• Translate research breakthroughs into reliable, production‑ready solutions.
• Optimise models for performance, latency, scalability and cost.
• Develop robust training and inference pipelines and debug complex production issues using real‑world data.
• Mentor engineers and drive engineering standards across the ML function.

Required profile

• Commercial experience delivering production ML systems.
• Strong Python software‑engineering background.
• Hands‑on experience with modern large‑language‑model training, fine‑tuning or deployment.
• Proficiency with PyTorch and/or JAX.
• Experience building scalable ML infrastructure and inference pipelines.
• Ability to own projects end‑to‑end in fast‑moving environments.
• Previous mentoring or technical leadership experience is a plus.

Required skills

• Python
• PyTorch
• JAX
• GPU training
• LLMs
• Modern ML infrastructure

What we offer

• Competitive salary range £80,000‑£180,000 per year.
• Equity participation.
• Fully remote work across Europe.
• Opportunity to shape a groundbreaking AI product from the ground up.