Role overview

Checkout.com is seeking a Senior Data Scientist to lead advanced optimisation initiatives and develop robust machine learning architectures. As a fintech company processing over 10 billion transactions yearly, Checkout.com powers payment systems for major platforms including eBay, Spotify, Klarna, Uber, and Sony. This role focuses on enhancing payment flows through data and machine learning services, tackling complex multi-objective optimisation challenges while collaborating with senior technical leaders.

Key responsibilities

Lead projects and design scalable architectures focused on multi-objective optimisation and advanced modelling.
Develop custom loss functions, evaluation frameworks, and tuning strategies that address complex business requirements.
Work with product stakeholders to align technical approaches with business objectives and remove cross-team obstacles.
Implement efficient data transformations using distributed computing tools such as Spark and Dask, while maintaining comprehensive test coverage for production systems.
Mentor junior team members and apply model explainability techniques to improve feature performance and understanding.

Requirements

At least five years of experience designing, building, and maintaining machine learning models to address large-scale, complex business challenges.
Deep knowledge of frequentist and Bayesian statistics, as well as supervised and unsupervised modelling approaches.
Demonstrated experience modelling complex interactions such as cluster or network effects.
Strong expertise in model explainability methods to guide feature engineering and feature interaction analysis.
Ability to write high-quality, production-ready Python code and communicate effectively with both technical and non-technical stakeholders.
Proficiency using large language models to support coding tasks and process optimisation.
Proven track record building trusted relationships with product stakeholders and understanding business models deeply.

What makes this role worth considering

Checkout.com operates with a hybrid working model requiring three days per week in the office, providing flexibility while fostering team collaboration. Based in London where the company maintains its headquarters, this role offers the opportunity to work on career-defining challenges within a fast-moving fintech environment across 20 global offices. You will collaborate with experienced Senior and Staff Data Scientists while driving innovation in decisioning systems that power digital commerce at scale.