Data Scientist – Fraud Detection (m/f/d)

Our requirements

• Strong Python for data analysis and machine learning (e.g. pandas, scikit-learn)
• Advanced SQL for analytical queries and feature generation
• Strong analytical and structured working style
• Experience with supervised learning as well as unsupervised methods such as clustering, outlier detection, or semi-supervised approaches
• Good understanding of overfitting, regularization, feature or label leakage, and its mitigation
• Hands-on exposure to validation strategies under production conditions
• Experience with cloud-based ML software stack
• Communication skills to understand business needs and generate business value

Optional

• Experience with AWS Stack
• Familiarity with fraud-specific metrics or cost-sensitive modeling
• Experience with Generative AI (e.g. for experimentation, exploration, or documentation)
• Basic understanding of software engineering concepts and APIs

Your responsibilities

• Analyze transactional and behavioral data to identify fraud patterns; perform data quality checks and exploratory analysis
• Prepare and document datasets for training, validation, and testing using SQL and Python
• Design fraud-relevant features and translate business logic into measurable signals
• Develop, evaluate, and improve supervised and unsupervised ML models for fraud detection
• Handle imbalanced, noisy real-world data and assess models using fraud-relevant metrics
• Analyze false positive / false negative trade-offs and provide model explainability (e.g. SHAP)
• Collaborate with developers and database teams to integrate ML outputs into the application
• Communicate results clearly to technical and non-technical stakeholders, including the customer

About the project

What we offer

• Employment contract? Of course. With us you do not have to worry about stable employment.
• Benefits? We have them! Among other: corporate incentive program, sport card, private medical care.
• Lunch card? With the cooperation extended and permanent contract, you will receive additional funds to use for meal purchases.
• Working in a hybrid model? Of course! ! You work with us 2 days a week from home.
• Work wherever you want? In PAYBACK you have the opportunity. Working 100% remotely, also from European countries for 15 days a year.
• ‎Flexible working hours? Sounds great! We start working between 7 to 10.
• Trainings? Of course. We provide training to develop hard and soft skills.
• Convenient location? Sure! We invite you to our new office at Rondo Daszyńskiego, but we are currently also working remotely.
• Dress code? We definitely say no. There are no rigid dress code rules in our company, sneakers are more than welcome.
• Friendly atmosphere at work? Yes! In PAYBACK, people are the most important asset‎.
• ‎Something is missing? Open communication is our priority, so dare to ask!‎

Benefits

• sharing the costs of sports activities
• private medical care
• flexible working time
• integration events
• no dress code
• pre-paid cards