Senior Data Scientist – AdTech & Healthcare (f/m/x)

Technologies we use

Expected

• Python
• PyTorch
• LightGBM
• Splink
• spaCy
• Hugging Face
• SQL
• Snowflake
• BigQuery
• Databricks

About the project

Tired of building yet another chatbot POC? Do you want to train ML models that bring real monetary value and run at a billion-scale? Do you feel like introducing a brand-new probabilistic methodology for a real-world problem?

We build the AI-powered operating system for healthcare marketing - programmatic advertising, data intelligence, patient affordability and AI-enabled engagement for the life sciences industry.

We are looking for a person who knows how to design and implement statistical methods to extract signals from large, messy, real-world datasets and use them for prediction. Everything we build on top of that, from audience reach to specialty insight to measurement, is only as good as your layer.

Your responsibilities

• Measuring existing model performance and finding ways to improve it
• Owning the design of the new methodology and training the next-gen model for increased predictive power, sample efficiency, and scalability to large datasets
• Extracting unique entities and sparse attributes from heterogeneous sources – both structured and unstructured
• Designing and implementing probabilistic entity linking & matching across multiple large healthcare datasets
• Exploring graph technologies and graph theory
• Building and owning an analytics data store, evaluation, and monitoring pipelines

Our requirements

• Minimum 5 years of experience in training and monitoring ML models for production use
• Experience with data and ML engineering, including ML-facing ETL processes over very large datasets and data-quality monitoring
• Expertise in Python data-science and ML libraries like scikit-learn, PyTorch, LightGBM, Splink, spaCy, and Hugging Face
• Practical experience in probabilistic methods for entity linking, matching, imputation, scoring, and evaluation
• Strong command of SQL for distributed warehouses such as Snowflake, BigQuery, or Databricks
• Advanced level of English

Optional

• Experience with graph technologies such as Neo4j, Amazon Neptune, Stardog, or similar platforms
• Familiarity with Graph Machine Learning concepts, including community detection, Graph Neural Networks (GNNs), and graph embeddings
• Exposure to AI-powered development tools such as Cursor AI, Claude Code, or equivalent solutions
• A proactive mindset with a willingness to take ownership of deliverables and contribute to product direction

What we offer

• Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas
• Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market
• We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022
• Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more
• Comfortable workplace – class A offices or remote work
• Dozens of fascinating projects for prestigious brands from all over the world – you can change them thanks to Job Changer application
• PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers
• Investment in your growth – meetups, webinars, training platform and technology blog – you choose
• Fantastic atmosphere created by all Sii Power People

Recruitment stages

• Send your CV
• Talk to us about your expectations
• Learn more about our projects and choose the best
• Start your adventure with Sii!

Sii Sp. z o.o.

Sii is the leading technology consulting, digital transformation, engineering, and business services vendor in Poland. We already employ more than 7 300 professionals and implement projects in a variety of industries for clients from many countries around the world. The Great Place to Work title, won 10 times in a row, proves that at Sii, we create a friendly work environment.

Sii ensures that all employment-related decisions are made solely on the basis of qualifications and competencies. We are committed to equal treatment of all individuals, regardless of any protected characteristics, and promoting a diverse and inclusive work environment.

This is how we work