Senior Data Scientist – Machine Learning & Recommendation Systems

Senior Data Scientist – Deep Learning & Recommendation Systems Hamburg, Germany (Hybrid) | Full-Time Are you interested in solving complex machine learning problems at scale? We are supporting an innovative technology company in Hamburg looking for a Senior Data Scientist to join a highly technical team developing large-scale deep learning solutions for recommendation, ranking and personalisation. You will work on production machine learning systems where advanced models directly influence user experiences and business outcomes, developing intelligent algorithms that understand behaviour, optimise relevance and deliver personalised experiences at scale. What You'll Do Build and optimise deep learning models for recommendation, ranking and personalisation Develop scalable machine learning solutions using modern deep learning techniques Work with large-scale datasets to improve model performance and user relevance Design experiments, evaluate model performance and validate new approaches Take ownership of ML models from research and development through to production deployment Collaborate closely with engineers and product teams to deliver measurable business impact Contribute technical expertise and best practices within the machine learning community What We're Looking For 7+ years of experience in Data Science, Machine Learning or Applied Science Extensive experience building production machine learning systems Strong hands‑on experience with deep learning frameworks such as PyTorch and/or TensorFlow Experience developing recommendation systems (RecSys), ranking algorithms or personalisation models Strong Python and SQL skills Experience working with large-scale production datasets Strong understanding of experimentation, model evaluation and production ML workflows Experience within the AdTech industry is essential. Candidates without commercial AdTech experience are unlikely to be considered. We are particularly interested in candidates from: AdTech companies (DSPs, SSPs, ad exchanges, mobile advertising or programmatic advertising) Recommendation systems or ranking teams Online advertising platforms Large-scale consumer technology companies with recommendation or advertising products Search, personalisation or marketplace ML teams What's Offered Competitive salary package up to €140,000, depending on experience International English-speaking environment Opportunity to work on technically challenging deep learning and recommendation systems Flexible working arrangements Strong opportunities for technical ownership and career growth If you're passionate about building large-scale deep learning systems and recommendation models in a fast-paced AdTech environment, we'd love to hear from you. Apply today or get in touch for a confidential discussion.