Senior Data Scientist

About the role

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.

Responsibilities

• 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 .
• What makes you great for this position
• 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 .
• Why you should join SumUp
• 🌎 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.
• 🌴 Break4me: 1-month sabbatical after 3 years of service.
• 🔗 Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team.
• About SumUp
• Our com mitment to small businesses is reflected in our diverse team of over 3,000 SumUppe rs from over 90 natio nalities, united by global collaboration and an i

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