Senior/Lead Data Scientist (Type B)

We're seeking a Senior/Lead Data Scientist (Type B) to build and scale our experimentation platform. This is an engineering-focused data science role that emphasizes system building over model development. The ideal candidate will create robust data pipelines, implement statistical methods at scale, and deliver production-ready solutions. This role bridges data engineering and statistical analysis, working with both BigQuery and local OLAP databases, and involves close collaboration with the Experimentation team who designs experiments with business stakeholders, and the DevOps team who manages infrastructure and deployments. 

If you want to:

• Enhance and maintain our experimentation platform that uses a layered architecture with BigQuery (DWH) and DuckDB (OLAP);
• Implement and validate statistical methods for A/B testing analysis
• Design and maintain statistical engines for hypothesis testing, power analysis, and experiment sizing;
• Develop new statistical features while ensuring mathematical correctness;
• Support Experimentation team with technical implementation of their test designs;
• Optimize data pipelines and ETL processes for handling experimental data;
• Improve platform scalability and performance while maintaining data integrity;
• Work closely with DevOps team on deployment and infrastructure requirements.

And you can check off:

• Relevant BSc or MSc and at least 5 years of industry experience;
• Ability to balance statistical rigor with practical implementation;
• Strong track record of building and maintaining data platforms;
• High proficiency in Python;
• Solid Unix/Linux environment experience;
• Experience with A/B testing platforms or experimentation frameworks would be considered as an advantage;
• Experience with various data bases, particularly DuckDB would be considered as an advantage;
• Experience with building Python based front-end applications, particularly Streamlit would be considered as an advantage;
• Strong communication skills to work with both technical and non-technical stakeholders;
• Self-motivated with ability to work independently;
• Ability to translate business requirements into technical solutions.

Here’s the deal:

• Growth and learning opportunities: time dedicated to learning, conferences, online learning platforms, and books for your professional development;
• Health and wellness: we want you to feel and be your best. That's why we offer various benefits, from online workouts with a physical coach and sports card to health insurance and regular mental health checks;
• Tools of your choice: choose the technical equipment and tools you need to do your best work;
• Community and celebrations: get ready for long-lasting traditions such as yearly workation, Friday get-togethers, various team buildings and company celebrations;
• Convenient commuting: traveling from point A to point B in a city like Warsaw is quite a journey! That’s why we compensate your public transport costs;
• Work-life balance: as a general rule, we work based on a 3+2 hybrid model. And let’s not forget the WFA policy – an opportunity to work from anywhere in the world;
• Premium Surfshark accounts: for you, your family, and friends!