EU Jobs
Senior Data Scientist (f/m/d)
Job Description
About the Role
This position sits within the Playtime Data Science team at adjoe, part of applike group. The team builds and scales machine learning systems that power one of the fastest-growing rewarded advertising ecosystems in mobile advertising.
At the core of the product is Playtime, a high-scale ad unit that rewards users for time spent and actions completed inside mobile games. The platform processes billions of ad requests daily, connecting advertisers with hundreds of millions of users worldwide.
As a Senior Data Scientist, you will design and deploy machine learning systems that directly influence user engagement, revenue optimisation, and advertising performance at global scale.
Key Responsibilities
Machine Learning & Modelling
- Translate complex product requirements into scalable ML solutions
Build predictive models for user behaviour, including LTV, conversion probability, and retention
Develop deep learning systems to improve ad targeting and monetisation performance
Continuously refine models based on real-time feedback and experimentation
Data Science Lifecycle Ownership
- Own the full ML pipeline from data extraction to production deployment
Analyse large-scale behavioural datasets (terabytes of user activity data)
Design and evaluate models using A/B testing frameworks
Ensure models perform reliably under high traffic conditions
Engineering & Collaboration
- Work closely with backend, infrastructure, and analytics teams
Ensure seamless integration of ML systems into production environments
Support system stability, scalability, and performance optimisation
Communication & Impact
- Present insights and model outcomes to product and business teams
Translate technical findings into clear business impact narratives
Influence product decisions through data-driven recommendations
About You
You are an experienced Data Scientist who enjoys solving high-impact, real-world problems using machine learning at scale.
Required Experience
- 5+ years in Data Science or Machine Learning roles
Proven experience deploying production ML models with measurable impact
Strong programming skills in Python
Experience with ML frameworks such as PyTorch, TensorFlow, Scikit-learn
Strong knowledge of data processing tools (Pandas, NumPy, Polars)
Experience with gradient boosting frameworks (XGBoost, LightGBM, CatBoost)
Advanced SQL skills with distributed data systems (e.g., Spark, Trino, AWS Athena)
Experience working with high-scale data environments (>1M predictions/day)
Ability to explain technical concepts to non-technical stakeholders
Willingness to relocate to Hamburg
Nice to Have
- Experience in AdTech, MarTech, or mobile advertising
Familiarity with ML infrastructure tools (Airflow, model deployment systems)
Experience with real-time or streaming data systems
What You Can Expect
- Career Growth
Structured development programs and regular performance feedback
Opportunity to grow into senior technical or leadership roles
Relocation & Support
- Full relocation assistance to Hamburg
Visa support and onboarding guidance
Relocation bonus to support settling in
Work Environment
- Hybrid working model with flexible hours
30 vacation days + additional remote work allowance
Modern office with Alster lake views, collaborative spaces, and full amenities
Free access to in-house gym and wellness activities
Mental health support via employee assistance programs
Culture & Community
- Regular hackathons and company-wide events
Strong engineering-driven culture with global teams
Social, collaborative, and innovation-focused environment
About the Company
adjoe is part of applike group and operates at the intersection of mobile advertising, AI, and large-scale data systems. Backed by significant investment and operating across multiple global locations, the company focuses on building next-generation advertising technologies that optimise engagement for users and revenue for publishers.
- EU Artificial Intelligence Act Overview
EU Data Strategy (Big Data & Digital Economy)
European Labour Mobility Portal (Data & Tech Jobs in EU)
German Federal Employment Agency – IT & Data Careers
EU Digital Skills & Jobs Framework