EU Jobs
Senior Data Scientist (f/m/d)
Job Description
About the Role
We are looking for an experienced Senior Data Scientist to join adjoe’s Playtime Data Science team in Hamburg.
This is a high-impact role at the intersection of machine learning, large-scale data systems, and ad-tech innovation. You will help shape how millions of users interact with mobile advertising by building intelligent systems that optimise engagement, monetisation, and user experience.
adjoe operates at global scale—processing billions of daily requests and connecting hundreds of millions of users through its rewarded advertising ecosystem.
What You Will Work On
Machine Learning & Product Impact
You will turn complex product challenges into scalable ML solutions that directly influence business performance.
- Design and deploy predictive models for user behaviour
Work on LTV (lifetime value), conversion, and retention prediction
Improve advertiser performance metrics such as ROAS
Build systems that dynamically optimise pricing and ad relevance
End-to-End Model Ownership
You will take full responsibility for the ML lifecycle.
- Analyse large-scale behavioural datasets (terabytes of data)
Develop and train deep learning models
Validate performance through A/B testing
Deploy models into production systems
Monitor and continuously improve model performance
Scalable Systems & Collaboration
You will work closely with engineering and analytics teams to ensure robust integration.
- Collaborate with Backend and Infrastructure teams
Ensure models are production-ready and stable at scale
Support high-throughput systems handling millions of predictions daily
Contribute to architecture decisions for ML pipelines
Data Analysis & Insights
- Use advanced SQL and distributed systems to extract insights
Work with tools such as Spark, Athena, or Trino
Translate complex datasets into actionable product decisions
EU digital economy insights
Communication & Stakeholder Work
You will bridge the gap between technical models and business strategy.
- Present findings to product and business teams
Translate technical outputs into clear product impact narratives
Help stakeholders understand ML-driven decisions
What You Bring
Experience
- 5+ years in Data Science or Machine Learning roles
Proven experience deploying models in production
Track record of measurable impact on business KPIs
Experience handling large-scale data environments
EU labour mobility information
Technical Skills
Strong Python expertise
- Experience with ML frameworks (PyTorch, TensorFlow, scikit-learn)
Familiarity with gradient boosting tools (XGBoost, LightGBM, CatBoost)
Advanced SQL skills
- Experience with distributed data systems (Spark, Trino, Athena)
Exposure to MLOps tools (Airflow, deployment pipelines)
Machine Learning Expertise
- Deep learning experience in production environments
Handling high-scale prediction systems (>1M predictions/day)
Strong understanding of model evaluation and experimentation
Communication & Thinking Style
- Ability to simplify complex mathematical concepts
Strong product intuition and problem-solving mindset
Comfortable translating between business and ML logic
Preferred
- Experience in AdTech, MarTech, or mobile advertising
Knowledge of infrastructure and model deployment workflows
Willingness to relocate to Hamburg
EU employment and relocation guidance
What We Offer
Career Growth
- Structured feedback and development programs
Opportunities to work on large-scale AI systems
High ownership of impactful ML products
Work Environment
- Hybrid working model (3 office days per week)
Flexible working hours
30 days annual leave
3 weeks remote work per year
EU working conditions framework
Relocation & Support
- Visa and relocation support for international candidates
Relocation bonus to help settle in Hamburg
Support for integration and onboarding
EU immigration & work guidance
Health & Wellbeing
- In-house gym with fitness classes
Mental health support via Employee Assistance Program
Work-life balance focused culture
EU health at work overview
Culture & Community
- Hackathons and technical challenges
Team events and social gatherings
Open, collaborative, engineering-driven culture
Modern office with views over the Alster lake
About adjoe (applike group)
adjoe is a fast-growing AdTech company backed by Bertelsmann, focused on redefining rewarded advertising and mobile monetisation.
The Playtime platform connects advertisers and publishers to hundreds of millions of users globally, using advanced AI systems to optimise engagement and revenue at scale.
Why This Role Matters
This position is ideal for someone who wants to:
- Build AI systems at massive global scale
Influence how billions of ad interactions are optimised
Work at the frontier of AdTech and machine learning
Collaborate with top engineering and data science teams
