Staff Data Scientist

About Marshmallow We exist to make migration easy. A systemic problem of this magnitude requires a team of curious thinkers who relentlessly pursue solutions. Those who constantly challenge the why, dismantle assumptions, and always take action to build a better way. A Marshmallow career is built on a cycle of continuous growth, with learning at its core. You will be challenged to raise the bar on your capabilities and supported with the right tools and guidance to do so. This ensures you can deliver impactful work and drive change. If life at Marshmallow sounds like it could be for you, explore our Culture Handbook to find out more. Move our mission, and your career, forward.

The role Data Science at Marshmallow Our Data Science team partners across the business to turn data into better decisions, smarter products, and simpler customer journeys. We work closely with Product, Engineering, and Operations to build and ship models and AI systems that are reliable in production and deliver measurable impact. Within Data Science, this role sits in Claims, supporting the function and the broader ambition to automate more of the claims journey. Claims is one of Marshmallow's most important customer touchpoints, and we're looking for a Staff Data Scientist who can provide technical leadership across traditional ML and Generative AI, bring system-level thinking to how we scale decisioning, and confidently challenge proposals to ensure we build robust, sustainable solutions.

Job requirements What you'll be doing Provide technical leadership for data science across Claims Fraud, shaping the approach to risk decisioning and fraud detection in partnership with Product and Engineering. Design, build and iterate on production ML and Generative AI/LLM systems that support claims validation and automation. Collaborate closely with other Claims data scientists to bring system-level thinking to how models, data and workflows fit together, identifying architectural improvements needed to scale decisioning and reduce time-to-production. Be vocal about the platform and tooling investments needed (monitoring, feedback loops, QA) to achieve AI-driven end to end claims automation. Advocate for robust, scalable, and strategically aligned technical solutions in cross-functional discussions, ensuring current systems and infrastructure contribute to the multi-year vision for automated claims handling. Set a high bar for statistical rigour, experimentation and measurement, helping improve how Claims performance and uncertainty are understood and communicated to senior stakeholders.

Benefits Perks of the job Flexible working: Spend three days a week with your team in our collaborative London office, and own your own working hours. The rest is up to you. Competitive bonus scheme - designed to reward and recognise high performance. Flexible benefits budget - £50 per month to spend on a Ben Mastercard meaning you get your own benefits budget to spend on things you want. Whether that’s subscriptions, night classes (puppy yoga, anyone?), the big shop or a forest of houseplants. Pretty much anything goes. Mental wellbeing support – Access therapy and mental health sessions through Oliva. Learning and development – Personal budgets for books and training courses to help you grow in your role. Plus 2 days a year - on us! - to further your skillset. Private health care - Enjoy all the benefits Vitality has to offer, including reduced gym memberships and discounts on smartwatches. Medical cash plan - To help you with the costs of dental, optical and physio (plus more!). Tech scheme - Get the latest tech for less.

Additional Information We are able to offer visa sponsorship for this position.