Senior Data Scientist

At SumUp, we're on a mission to empower small businesses across the globe by providing a vast set of simple and affordable business tools to help them start, run, and grow their businesses. Lending at SumUp is a mature, scaled business with a strong and proven credit risk foundation. Our core models and decisioning frameworks are already robust and in production; as our portfolio grows, our challenge is safely extracting marginal gains from a complex system where changes are incremental and the stakes are high. As a Senior Data Scientist, you will be highly hands-on and embedded in day-to-day lending decisions. This role exists to strengthen our ability to improve what already works, reduce operational risk, and ensure long-term reliability as we scale into new markets. You will work within the Credit Risk Analytics (CRA) team, a streamlined group responsible for the modeling and analytics that underpin our global lending portfolio., * Optimise Credit Risk Models: Iterate on existing models to improve stability, predictive power, and net revenue impact while performing deep dives to support risk decisions.

• Drive End-to-End Deployment: Develop, test, and deploy new model versions in close collaboration with Credit Risk Engineering (CRE), ensuring no regressions or operational issues.
• Enhance ML Infrastructure: Improve machine learning pipelines and workflows to reduce maintenance overhead and failure modes.
• Integrate New Data: Evaluate and integrate new internal and external data sources (e.g., credit bureaus, open banking) into existing models and processes.
• Monitor Performance: Closely monitor models in production, investigating performance shifts or anomalies to maintain portfolio integrity.
• Promote Technical Excellence: Document work clearly and participate in code reviews, design discussions, and pair programming to maintain high-quality standards.

Do you have experience in SQL?, * 5+ years of experience as a Data Scientist (or 7+ years in data-related/software engineering fields with at least 3 years in Data Science).

• MUST HAVE experience working with Credit Risk.
• Deep understanding of Data Science principles, including statistics, probability theory, and machine learning concepts.
• Strong experience with Python (pandas, PySpark, scikit-learn) and SQL for complex data retrieval and manipulation
• Proven track record of building, evaluating, and deploying machine learning models end-to-end at scale.
• Experience with credit risk assessment, lending, or financial decisioning models.
• Strong software engineering practices, including writing clean, maintainable, testable code with version control and documentation.
• Collaborative and respectful team player who is comfortable voicing disagreements while committing to team decisions ("disagree and commit").
• Fluency in English with the ability to communicate technical findings clearly to diverse stakeholders.

Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our Barcelona office.

Commitment to Diversity and Inclusion: be part of a workplace that values and promotes diversity, fostering an inclusive environment where everyone's perspectives are respected and embraced.

Enrolment onto our Virtual Stock Option programme: you will own a stake in SumUp's future success.

A dedicated annual L&D budget of €2000 for your individual development, which you can be used to attend conferences and/or advancing your career through further education.

A corporate pension scheme where we match up to 20% of your contributions.

️ Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days.

️ Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, subsidised office lunches.