Senior Data Scientist

The role

You will lead advanced optimisation projects and champion the development of robust, sustainable ML architectures. You will enhance payment flow through data and ML services and work with other Senior and Staff Data Scientists to shape decisioning system architecture.

What you will do

• Lead projects and architecture design for multi-objective optimisation and scalable models.
• Create custom loss functions, evaluation, and tuning frameworks.
• Collaborate with product stakeholders to align technical strategy with business goals.
• Apply efficient data transformations using distributed computing.
• Ensure robust test coverage for production systems.
• Mentor junior team members.
• Utilise model explainability methods to drive feature performance improvements.

Required qualifications

• 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.
• Ability to collaborate effectively with non-technical stakeholders.
• Proficient in leveraging LLMs for coding support and process optimisation.
• Adept at tuning technical communication for broad audiences.
• Proven ability to build trusting relationships with product stakeholders and deeply understand business models.

Nice to have

• 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.

About the company

Checkout.com enables over 10 billion transactions yearly for more than one billion global shoppers. The company has 20 offices across six continents with London as HQ.