Principal Machine Learning Scientist, Recommender Systems

Relay is fundamentally reshaping how goods move in an online era. Backed by Europe’s largest-ever logistics Series A ($35M) led by deep-tech investors Plural, and a recently closed Series B ($95M), Relay is scaling faster than 99% of venture-backed startups.

As a Principal Machine Learning Scientist at Relay, you'll set the standard for recommender systems at Relay, lead the evolution of Relay's recommender from research to production, design and build the recommender systems that power Relay's key decisions, partner with Operational Research to unite recommender models and optimisation, and contribute to Relay's research culture.

We're looking for candidates who have built recommender systems at scale, owned them in production, and led their direction. You should bring deep expertise in recommender systems, reinforcement learning and LLMs, think in experiments, and let evidence guide decisions.

The team at Relay consists of around 160 people, with around half in engineering, product and data, and 45+ advanced degrees across computer science, mathematics and operations research.

Relay is an equal-opportunity employer committed to diversity, inclusion, and fostering a workplace where everyone thrives.