Senior Machine Learning Engineer - Messaging Platform

Spotify's Subscriptions Mission focuses on converting listeners into lifelong subscribers. The Messaging Platform powers Spotify's communications to over a billion users — from push notifications to emails and in-app messages. Within this space, the Paloma squad focuses on message optimization: deciding which message reaches which user, through which channel, and at what moment.

What You'll Do

• Design, build, and ship machine learning models that optimize messaging across push, email, and in-app channels.
• Plan and run A/B experiments in a multi-objective environment, balancing conversion, engagement, retention, and reachability.
• Contribute to reinforcement learning systems that optimize for long-term user outcomes.
• Own the full ML lifecycle, from data and modeling to deployment, monitoring, and iteration.

Who You Are

• You have strong experience building and deploying machine learning models in production environments at scale.
• You bring hands-on experience with PyTorch and distributed systems such as Ray or similar frameworks.
• You have experience with or curiosity about reinforcement learning and long-term optimization systems.

Where You'll Be

• This role is based in London and Stockholm.
• We offer you the flexibility to work where you work best! There will be some in person meetings, but still allows for flexibility to work from home.