# Principal Data Scientist at marshmallow

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> Responsibilities: - Provide strategic technical leadership a

- **Company:** marshmallow (https://jobs.trythestack.co/companies/marshmallow)
- **Location:** London, United Kingdom
- **Work arrangement:** Hybrid
- **Employment type:** Full-time
- **Experience level:** 10+ years
- **Visa sponsorship:** Offered, according to the listing
- **Key skills:** Machine learning, Generative AI, LLM, Risk-based decisioning, Fraud detection, Statistical rigour, System-level thinking, Technical leadership, Stakeholder management, Production deployment, Data science, Product strategy, Engineering collaboration, Automation, Experimentation
- **Posted by employer:** 2026-10-06
- **Added to The Stack:** 2026-10-07
- **Listed until:** 2026-12-05
- **Status:** Active
- **Apply:** https://jobs.ashbyhq.com/marshmallow/9c4c710f-6e8a-4081-84ad-325d58832e3b (the employer's own application page)
- **Human page:** https://jobs.trythestack.co/jobs/principal-data-scientist-marshmallow

## About the role

Responsibilities:
- Provide strategic technical leadership across Claims to define and deliver multi-year ML and Generative AI roadmaps (fraud, validation, automation).
- Architect robust, scalable decisioning systems that integrate models, data pipelines and operational workflows across teams.
- Drive platform investments (monitoring, QA, feedback loops) and governance to ensure safe, measurable model behaviour in production.
- Challenge and influence product and engineering proposals to keep solutions maintainable, secure and aligned to business objectives.
- Lead experimentation strategy, set statistical standards and ensure model uncertainty and performance are communicated to senior stakeholders.
- Coach senior data scientists and shape cross-functional practices for deployment, validation and ongoing model operations.

Requirements:
- Extensive experience delivering production ML and GenAI/LLM systems at scale and shaping technical strategy across teams.
- Strong background in system architecture, monitoring, governance and model lifecycle management.
- Demonstrated ability to influence senior stakeholders and translate business goals into technical programmes.
- Deep statistical rigour, experimentation experience and familiarity with operational constraints in insurance/financial products.
- Excellent collaboration and leadership skills; ability to mentor technical staff and work closely with engineering and product.

## Responsibilities

Provide technical leadership for data science within the Claims department, focusing on fraud detection and risk decisioning. Design and deploy production-grade machine learning and Generative AI systems to automate and improve the claims journey.

## Requirements

Requires significant commercial experience in end-to-end machine learning and hands-on experience shipping Generative AI systems in production. Candidates must possess a strong statistical foundation and the ability to influence technical direction across cross-functional teams.

## FAQ

- **Is this Principal Data Scientist role still open?** It was posted on 2026-10-06 and is listed as active on The Stack. Confirm on marshmallow's application page before applying.
- **Does marshmallow offer visa sponsorship?** This listing is marked as offering visa sponsorship. Eligibility rules are set by the employer, so check the details on marshmallow's site.
- **Where is this role located?** The listing gives the location as London, United Kingdom. It is marked hybrid.
- **What skills does this role ask for?** The listing names: Machine learning, Generative AI, LLM, Risk-based decisioning, Fraud detection, Statistical rigour, System-level thinking, Technical leadership, Stakeholder management, Production deployment, Data science, Product strategy, Engineering collaboration, Automation, Experimentation.

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## Notes for agents

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