Principal Data Scientist, Marshmallow
+ Bonus
More information about location
We’re building a huge technology company that helps make moving country easier.
Open for applications
We’re building a huge technology company that helps make moving country easier.
501-1000 employees
Open for applications
+ Bonus
More information about location
501-1000 employees
Company mission
To back those who find themselves on a different path, either by choice or by circumstance, helping the exceptions to the rules that others aren’t interested in serving.
Role
Who you are
- You think in systems: you can connect the dots between data science, engineering, and product to shape scalable solutions that build on each other over time
- You're confident in challenging assumptions and pushing for the right approach, using strong communication skills to influence stakeholders across seniority levels and disciplines with clear, pragmatic reasoning
- You thrive in ambiguity and change, staying resilient and effective during transitions while bringing structure, clarity, and momentum to complex problem spaces
- You're motivated by real-world impact, partnering closely with cross-functional teams to drive meaningful automation and better customer outcomes across the claims journey
- Significant commercial experience delivering end-to-end Machine Learning solutions, from problem framing and experimentation through to production deployment and ongoing monitoring
- Hands-on experience building and shipping Generative AI systems in production (not just prototypes), including evaluation, safety/quality considerations, and integration into customer or operational workflows
- Strong statistical and modelling foundation, with experience in risk-based decisioning under uncertainty (e.g., fraud, credit, insurance, or other regulated domains)
- Proven ability to influence technical direction across Data Science and Engineering, including shaping scalable model/service integration patterns and challenging proposals to drive robust, long-term solutions
- Strong stakeholder management skills, with confidence communicating trade-offs and pushing back constructively with Product and Engineering to ensure high-quality outcomes
What the job involves
- 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 Claims Fraud 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 Principal 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
- 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
Application process
- Initial call with a member from our Talent Team (30 mins)
- Past Experience interview with Hiring Manager (60 mins)
- Systems Design interview with a couple of the team (60 mins)
- Technical interview with a couple of the team (60 mins)
- Culture interview (60 mins)
Salary benchmarks
Our take
For many ordinary people, insurance can be inaccessibly expensive. Marshmallow solves this problem by using data and technology to offer fairer access to products like insurance and financial support, starting with coverage for car and van owners.
Traditional providers often rely on broad population averages, meaning individuals are frequently overcharged based on age, nationality, or background. Marshmallow takes a different approach, leveraging proprietary tech to deliver personalise, more accurate quotes in minutes. This has led to better rates for customers and a surge of positive reviews and recognition since the company's launch.
Now operating as a fintech scale-up, Marshmallow is expanding its reach beyond just vehicle insurance. The company is also exploring areas like home insurance and wider financial services, with the aim of supporting those who are often left out of traditional systems. Having achieved unicorn status and doubled its profit since 2023, Marshmallow is well-positioned for this next chapter.
Kirsty
Company Specialist at Welcome to the Jungle
Insights
Company
Funding (last 2 of 5 rounds)
Apr 2025
$90m
SERIES C
Sep 2021
$83m
SERIES B
Total funding: $208.2m
Company benefits
- Flexible working - Manage your own time flexibly. Just make sure your team is happy too.
- Ben benefits - Get your hands on your flexible benefits budget with the Ben Mastercard and spend it wherever you want.
- Competitive bonus scheme - designed to reward and recognise high performance 🌟
- Private healthcare - We want to support everyone’s wellbeing at Marshmallow, which is why we offer private healthcare insurance with Vitality.

- Cycle to work scheme - We’re registered under the Cycle-to-Work scheme, so you can buy a new bike tax-free. Lycra shorts optional.
- Mental wellbeing - We have partnered with Oliva to offer mental health support and make therapy sessions more accessible.
- Learning and training - Personal budgets for books and training courses to help you grow in your role. Weekly book clubs and learning sessions. Plus 2 days a year - on us! - to further your skillset.
- Company socials - We give all of our teams monthly budgets to get to know each other better outside of work. Plus we have company-wide socials every two weeks, themed parties, and more.
Company HQ
Old Street, London, UK
Leadership
Oliver Kent-Braham
(Co-CEO)Previously worked in Growth & Partnerships at Yoti and Leveraged Finance at Investec. Previously founded Reel Money.
Alexander Kent-Braham
(Co-CEO)Previously worked in Product at Yoti. Also co-founded Reel Money and was an Analyst at hedge fund QCM.
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