Data Scientist
SumUp · Berlin, Berlin, Germany
- On site
- Full-time
- €70,000 / year
- Berlin, Berlin, Germany
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Job highlights
- Develop AI and ML models for customer support.
- Evaluate AI product quality and effectiveness.
- Collaborate with cross-functional teams.
- Build and improve data pipelines and models.
- Drive measurable improvements in customer experience.
About the role
About the team:
Within Global Operations, our mission is to deliver the best customer experience in the fintech industry by providing an effortless, high-quality experience for every merchant. We are looking for a skilled and passionate Data Scientist to join our AI Team, contributing to the development of customer-facing models and the evaluation of our AI products. Your work will help elevate our customer support by improving quality, identifying gaps, and tailoring the experience to merchants’ needs.
As a Data Scientist at SumUp, you will design, test, and implement both traditional machine learning and AI models, while also assessing the effectiveness of our AI products. You will have a direct impact on company performance by developing and scaling evaluation methods that measure service quality across agents and AI assistants, identify opportunities for improvement, and ensure we deliver the right support experience for each merchant segment.
You will collaborate closely with cross-functional partners — including analysts, ML engineers, data scientists, and product managers — to translate business needs into measurable, production-ready ML solutions. Your contributions will help shape the future of our customer support experience and enable SumUp to grow sustainably with a strong customer-first focus.
What you’ll do:
- Build and improve LLM-based evaluation models (LLM-as-a-Judge) to assess the quality, safety, and effectiveness of AI products (e.g., AI assistant outputs, agent copilots, support automation).
- Help design and implement automated QA and evaluation pipelines that enable continuous monitoring and benchmarking of AI product performance at scale.
- Contribute to end-to-end model development, from problem framing and data exploration to deployment and monitoring, with guidance and support from the team.
- Own the forecasting models and work with WFM to improve the accuracy.
- Develop and maintain data pipelines that combine product signals, customer support interactions, and feedback loops to support reliable evaluations and insights.
- Support the creation of qualitative and quantitative observability frameworks, including rubrics, evaluation criteria, labeling strategies, and error categories to understand model performance and failure modes.
- Produce actionable insights from evaluation outputs to identify gaps and improvement opportunities, and communicate recommendations to product and operations stakeholders.
- Build and iterate on ML models (AI or traditional) that improve support efficiency, such as prediction models for routing, deflection, resolution likelihood, or quality scoring.
- Collaborate closely with data scientists, analysts, ML engineers, and product managers to deliver measurable improvements to customer support experiences.
- Learn and share best practices across the data and AI community at SumUp, contributing to a culture of continuous improvement.
You’ll be great for this position if you have:
- 3+ years of experience applying data science to real-world products, ideally in AI systems, customer support, quality measurement, or evaluation frameworks.
- Solid understanding of machine learning and statistics, including experimentation and metric design.
- Experience working with LLMs or NLP systems, and interest in evaluation methods (e.g., rubric-based scoring, prompt-based judges, calibration approaches, or human-in-the-loop evaluation).
- Strong ability to write clean, reliable code in Python (pandas, numpy, scikit-learn) and strong working knowledge of SQL.
- Experience building or contributing to data workflows and pipelines, and familiarity with taking models into production environments.
- Confidence communicating results and insights to both technical and non-technical stakeholders, with a strong focus on practical business impact.
- A proactive mindset and willingness to take ownership of tasks while collaborating closely with the team in a fast-paced setting.
Why you should join SumUp:
- Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our Berlin office. This involves an office-first setup.
- 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.
- A dedicated annual L&D budget for attending conferences and/or advancing your career through further education.
- A corporate pension scheme where we match up to 20% of your contributions.
- Enjoy the unique opportunity to take a well-deserved break with our 30-day sabbatical benefit after completing 3 years of employment with SumUp.
- Earn additional rewards by referring talented individuals to join the SumUp team.
About us:
SumUp is a leading financial technology company, founded in 2012 with the goal of empowering small businesses around the globe. We’re the financial partner of choice for more than 4 million merchants in over 35 markets. We collectively build, plan and fine-tune the technology that drives SumUp and empowers small businesses around the world.
We believe in the everyday hero. Those who have the courage to follow their passion and who have the strength and determination to realise their dreams. Small business owners are at the heart of all we do, so we're creating powerful, easy-to-use financial solutions to help them run their business.
Key skills/competency:
- Data Science
- Machine Learning
- AI Products
- LLM Evaluation
- Python
- SQL
- Data Pipelines
- Model Deployment
- Customer Support
- Fintech
Skills & topics
- Data Scientist
- Machine Learning
- AI
- LLM
- Python
- SQL
- Data Pipelines
- Fintech
- Customer Support
- Model Evaluation
How to get hired
- Tailor your resume: Highlight your Python, SQL, ML, and LLM experience, focusing on AI systems and customer support projects.
- Showcase impact: Quantify your achievements in previous data science roles, emphasizing business impact and problem-solving skills.
- Prepare for technical interviews: Brush up on machine learning concepts, statistics, Python coding, and SQL querying.
- Demonstrate collaboration: Be ready to discuss how you've worked with cross-functional teams to deliver data-driven solutions.
- Research SumUp's values: Understand their customer-first focus and commitment to empowering small businesses to align your application.
Technical preparation
Behavioral questions
Frequently asked questions
- What are the key responsibilities of a Data Scientist at SumUp?
- As a Data Scientist at SumUp, you will be responsible for designing, testing, and implementing machine learning and AI models, particularly those focused on customer-facing applications and AI product evaluation. This includes building LLM-based evaluation models, developing automated QA pipelines, owning forecasting models, and producing actionable insights to improve customer support.
- What technologies and tools are essential for this Data Scientist role at SumUp?
- Proficiency in Python (pandas, numpy, scikit-learn) and SQL is essential. Experience with machine learning, statistics, LLMs, NLP systems, and building data workflows/pipelines is also crucial. Familiarity with deploying models into production environments is highly valued.
- What is the expected experience level for the Data Scientist position at SumUp?
- SumUp is seeking a Data Scientist with at least 3 years of experience applying data science to real-world products. Experience in AI systems, customer support, quality measurement, or evaluation frameworks is particularly relevant.
- How does SumUp foster a culture of learning and development for its Data Scientists?
- SumUp offers a dedicated annual L&D budget for conferences and further education. They also encourage sharing best practices across the data and AI community within the company, contributing to a culture of continuous improvement.
- What is SumUp's approach to hybrid or remote work for Data Scientists?
- The role is described as an 'office-first setup' in their Berlin office, suggesting a preference for on-site or potentially a hybrid arrangement. It's best to clarify the specifics of the work arrangement during the application process.
- How does SumUp support the professional growth of its Data Scientists?
- SumUp supports professional growth through a dedicated annual L&D budget, opportunities to work on large-scale fintech products, and a culture that encourages continuous learning and sharing best practices. They also offer a 30-day sabbatical after three years of employment.
- What kind of impact can a Data Scientist have at SumUp?
- A Data Scientist at SumUp can have a direct impact on company performance by developing and scaling evaluation methods for AI products, identifying improvement opportunities in customer support, and influencing the future of customer experience for millions of merchants globally.