Principal ML Scientist - Recommender, Scale & Impact

Relay Technologies; Greater London; Hybrid; GBP 120,000 - 180,000; Full time

Job summary

Relay is seeking a Principal Machine Learning Scientist to set the standard for recommender systems and to advance Relay's technology from research to production.

You will design and build scalable recommender models, lead reinforcement learning and LLM initiatives, and partner with Operational Research to align models with optimization.

Join a fast‑growing, mission‑driven team where experimentation, rigorous evaluation and clear communication drive impact for merchants, couriers and customers.

Responsibilities

• 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.
• Contribute to Relay's research culture, and develop our voice in the tech community.

Job description

Relay is seeking a Principal Machine Learning Scientist to set the standard for recommender systems and to advance Relay's technology from research to production.

You will design and build scalable recommender models, lead reinforcement learning and LLM initiatives, and partner with Operational Research to align models with optimization.

Join a fast‑growing, mission‑driven team where experimentation, rigorous evaluation and clear communication drive impact for merchants, couriers and customers.