primer.io - Senior ML Engineer

• Senior experience in ML engineering, data science, or applied research, with real production deployments behind you (API, batch, or streaming) • You think statistically. You can design and run experiments and A/B tests, and report what the results do and don't show • Strong Python skills and hands-on experience with ML libraries such as scikit-learn, XGBoost, TensorFlow, PyTorch or Keras • Solid grounding in modern software engineering, infrastructure and data tooling, and an understanding of the MLOps challenges across the full ML lifecycle. You don't need to have built a platform, but you know what one has to handle • Familiarity with reinforcement learning (multi-armed or contextual bandits, for example). Production experience with it isn't required, but you need to understand how it works and where it applies • Cloud experience — AWS preferred; GCP or Azure both fine • Exposure to payments or e-commerce is a plus, not a prerequisite - you'll build that domain depth on the job • Comfortable with ambiguity, in the problems and in the process. You can research, develop and productionise independently, and you'll help define how we work as you go • YOU MAY NOT LIKE IT HERE • You enjoy working in an office setting — we're remote-first, and always will be • You need a fully mapped-out roadmap before you start — we're building this function, and there is a lot yet to be defined. • You prefer handing models to another team to deploy and run. • ✅ A TYPICAL INTERVIEW PROCESS • An initial intro call with a Talent Partner • An interview with the Hiring Manager • Challenge Stage - Contextualised to the role • A final, values-alignment interview • WHAT'S THE CULTURE LIKE AT PRIMER? • We're building a culture where people can do their best work and be proud of the impact they have. You'll be working with people who are mission-driven, smart, and reflective, and who are genuinely invested in building exceptional products and delivering success for our merchants. • We work remotely, and have done since day one. We believe that building a successful, profitable company goes beyond proximity. We invest in our relationships through great remote working practices and thoughtfully designed face-to-face time, including workations, our annual company retreat, and access to co-working spaces across most major cities. • The work is challenging. Scaleups are a challenge, and building category-defining products is a challenge. But there's a meaningful difference between a challenge and a struggle. At Primer, the right challenge comes with the right support: strong onboarding, a collaborative environment, and a team that is genuinely invested in your success. It's never something you face alone.