Senior Data Scientist

About the role

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 enhancing payment flow through data and ML services, advancing the complex problem of multi‑objective optimisation, and working closely with other senior and staff data scientists to shape the architecture of our decisioning systems.

Key responsibilities

• 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.

Required profile

• 5+ years of experience designing, building and maintaining machine learning models for large‑scale business problems.
• Deep understanding of frequentist and Bayesian statistics, plus supervised and unsupervised modelling techniques.
• Proven experience modelling complex interactions such as 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.
• Adept at tailoring technical communication for broad audiences.
• Proven ability to build trusting relationships with product stakeholders and deeply understand business models.