Senior Data Scientist — Growth & Personalization

Joinimagine; Województwo mazowieckie; On-site; PLN 180,000 - 280,000; Full time

Benefits offered by this job

Workspace in Warsaw Centre Point

Global collaboration across HelloTech

Job summary

HelloFresh in Warsaw, within HelloTech, is seeking a Senior Data Scientist to drive ML-powered personalization across conversion funnels and support data-driven growth for a global customer base.

You will partner with Product and Engineering to design, implement, and evaluate ML models, ensuring safe and scalable delivery in a high-traffic environment. This role emphasizes collaboration and impact across international teams.

Qualifications

• 5+ years of professional experience in data science or a related quantitative field.
• Strong foundation in machine learning concepts relevant to personalization and marketing.
• Hands-on experience with regression, classification, clustering, recommendation systems, and experimentation.
• Experience designing and analyzing A/B tests and controlled experiments.
• Experience working with customer behavior data and segmentation.
• Extensive experience operating in production environments and collaborating with engineers.
• Clear, structured communication skills and a collaborative mindset.

Responsibilities

• Build and iterate on machine learning models powering personalization that run in production behind high-traffic, performance-critical conversion pages.
• Execute decisioning models that determine the best next step in the conversion funnel for each user.
• Contribute to system design by coordinating with Engineering to ensure data science solutions integrate into the funnel architecture.
• Coordinate with Product and Engineering to embed ML-driven decisions into the conversion funnels, including where models decide and how failures are handled.
• Direct experimentation design for decisioning models, defining success metrics, guardrails, and interpretation in high-noise environments.
• Maintain model safety and effectiveness in production by monitoring performance, data reliability, and latency.

Skills

Data science

ML for personalization

A/B testing

Production ML

Cross-functional collaboration

Communication

Tools

Python

SQL

ML frameworks

Job description

HelloFresh in Warsaw, within HelloTech, is seeking a Senior Data Scientist to drive ML-powered personalization across conversion funnels and support data-driven growth for a global customer base.

You will partner with Product and Engineering to design, implement, and evaluate ML models, ensuring safe and scalable delivery in a high-traffic environment. This role emphasizes collaboration and impact across international teams.