Senior Machine Learning Data Scientist – Advertising & Ranking

Unleash innovative machine learning solutions — drive impactful advertising intelligence and ranking excellence!
Warsaw-based opportunity with hybrid work model.

As a Senior Data Scientist, you will be working for our client, a leader in digital advertising and bidding systems, committed to transforming data into strategic signals that optimize ad performance and revenue. Your expertise will shape the development, refinement, and deployment of sophisticated ML models directly impacting real-time bidding, ranking, and user engagement strategies, fostering innovation and career growth at the forefront of ad tech.

Your main responsibilities:

• Drive the design, training, and evaluation of ML scoring models (e.g., CTR, CVR, RoAS) critical for core bidding logic.
• Architect and implement complex model strategies integrating user, product, and placement signals for high-throughput, low-latency environments.
• Collaborate with engineering and business stakeholders to translate strategic goals into measurable modeling outcomes and technical roadmaps.
• Lead end-to-end development, deployment, and monitoring of production ML systems, ensuring alignment with industry standards and performance metrics.
• Review and improve code quality, experiment tracking, and model lifecycle management within ML pipelines, emphasizing reproducibility.
• Optimize SQL queries on large-scale data warehouses such as BigQuery, applying best practices for performance and scalability.
• Guide and mentor junior data scientists on state-of-the-art modeling techniques, feature engineering, and production ML best practices.
• Stay ahead of industry trends in online ranking, low-latency systems, and ML Ops solutions to foster innovation.

You're ideal for this role if you have:

• 5+ years of hands-on experience in designing, training, and deploying deep learning models in production environments.
• Expertise in Python, PyTorch or TensorFlow, with practical knowledge of ML lifecycle management and scalable pipelines.
• Strong SQL skills for large-scale data processing (e.g., BigQuery) and optimizing complex queries.
• Proven experience with ML Ops practices, including CI/CD, Docker, MLflow, and cloud environments (preferably GCP).
• Familiarity with online advertising or ranking systems, including CTR, CVR, RoAS modeling, and low-latency deployment.
• Fluency in Polish and a good command of English.
• Eligibility to work in the EU.

It is a strong plus if you have:

• Experience with GCP Vertex AI and Vertex Pipelines.
• Background in ad tech, ranking, or online bidding.
• Certifications in MLops or cloud platforms.

#MAKEYourCareerBETTER
Interested? Apply now and include your CV (preferably in English) along with a statement confirming your consent to the processing and storage of your personal data.