Senior Data Scientist

About the role

We are looking for a talented Senior Data Scientist to join our fast‑growing R&D team at Start.io, a mobile data platform that powers real‑time decision‑making for billions of users worldwide.

Key responsibilities

• Analyze large, complex datasets to uncover hidden patterns and business opportunities.
• Design, develop, and own end‑to‑end highly scalable data pipelines.
• Build state‑of‑the‑art machine‑learning models and algorithms for monetisation and recommendation use‑cases.
• Provision data models for real‑time (online) processing and shape new data products.
• Collaborate with Product, BI, Analytics, DevOps, R&D and Marketing teams to deliver integrated solutions.
• Oversee full production releases, including testing, monitoring, and rapid issue response.

Required profile

• B.Sc./M.Sc. in Computer Science, Engineering, Mathematics, Statistics or related field.
• Minimum 6 years of experience as a Data Scientist with strong ML expertise.
• Hands‑on experience with Python and ML libraries (e.g., XGBoost, LightGBM, recommendation systems).
• Proficiency in SQL and database querying.
• Familiarity with monitoring and alerting tools such as Grafana or Kibana.

Required skills

• Python
• XGBoost / LightGBM
• Recommendation system algorithms
• SQL
• Grafana
• Kibana
• Vertica or VoltDB
• MongoDB
• PMML

What we offer

• Supportive HR team and a collaborative environment.
• 20 days of vacation.
• Health insurance and Multisport coverage (Poland).
• Software purchase assistance.
• Mobilisation reservation for Ukrainian colleagues after probation.
• Competitive compensation.