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# Senior Data Scientist

- **Company:** Checkout.com
- **Location:** London, UK
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Amazon Web Services, Code Coverage, Distributed Systems, Python (Programming Language), Machine Learning, Recommender Systems, Azure Machine Learning, Feature Engineering, Large Language Models, Apache Spark, Dask, Docker
- **Published:** July 23, 2026
- **Apply:** https://uk.indeed.com/viewjob?jk=0d0398b5e47bb2ba

## About the Role

* 5+ years of experience in designing, building and maintaining machine learning models to solve complex, large-scale business problems.
 * Deep understanding of frequentist and Bayesian statistics, plus supervised and unsupervised modelling techniques.
 * Proven experience modelling complex interactions (e.g., cluster or network effects).
 * Expertise in model explainability to tune feature engineering and understand feature interactions.
 * Ability to write high-quality, production-grade Python code and collaborate effectively with non-technical stakeholders.
 * Proficient in leveraging LLMs for coding support and process optimisation to maximise personal and team productivity.
 * Adept at tuning technical communication for broad audiences.
 * Proven ability to build trusting relationships with product stakeholders and deeply understand business models., * Experience with distributed general-purpose cluster-computing.
 * Proven experience designing and deploying recommender systems, contextual bandits, or network intelligence applications.
 * Experience in fintech, payments or similar domains.
 * Experience with Docker, AWS/GCP, and modern ML deployment practices.

## Description

Checkout.com is looking for an experienced Senior Data Scientist to lead advanced optimisation projects and champion the development of robust, sustainable ML architectures. You will be responsible for the enhancing payment flow through data and ML services, advancing the complex problem of multi-objective optimisation. You will work closely with other Senior and Staff Data Scientists to shape the architecture of our decisioning systems., * Lead projects and architecture design for multi-objective optimisation and scalable models.

 * Create custom loss functions, evaluation, and tuning frameworks that reflect complex business problems.
 * Collaborate with product stakeholders to align technical strategy with business goals and resolve blockers across the team.
 * Apply efficient data transformations using distributed computing (e.g., Spark, Dask) and ensure robust test coverage for production systems.
 * Mentor junior team members and utilise model explainability methods to drive feature performance improvements.


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