Senior Data Scientist

We are The Codest - International Tech Software Company with tech hubs in Poland delivering global IT solutions and projects. Our core values lie in a “Customers and People First” approach that prioritises customer needs and a collaborative environment for employees. Our expertise includes web development, cloud engineering, DevOps, and quality. We developed Yieldbird, a product honored in the Top25 Deloitte awards, and focus on helping tech companies build impactful products and scale their IT teams. Our client is one of the largest e-commerce platforms in Europe, serving millions daily by connecting sellers and customers with a broad product selection and fast delivery.

• Extensive hands-on experience designing, training, and improving Deep Learning models for business-critical production use cases.
• Proven expertise with deep learning frameworks such as PyTorch or TensorFlow, and practical knowledge of Pandas and NumPy.
• Advanced SQL skills, preferably including analytical SQL for large-scale data environments.
• Strong experience with public cloud infrastructure, preferably Google Cloud Platform, including ML services like Vertex AI and Vertex Pipelines.
• Proven ability to lead end-to-end model development from problem framing to production handoff.
• Strong engineering foundations, including writing production-level, testable, documented Python code, and familiarity with CI/CD practices.
• Ability to mentor other Data Scientists and raise modeling standards team-wide.
• Relevant academic degree or extensive professional experience in a STEM field (e.g., Computer Science, Mathematics, or Physics).
• English proficiency minimum level B2.

Nice to have:

• Experience developing ML models for low-latency online applications.
• Experience within advertising or marketing domains.
• Experience developing ML models predicting business events such as Click-Through Rate (CTR) and Conversion Rate (CVR).
• Proficiency in traditional machine learning techniques like Gradient Boosted Trees.
• Experience in mentoring, technical leadership, or coordinating model development across teams.
• Practical use of AI-assisted coding tools to improve engineering productivity and quality.

• Drive the design, refinement, and evaluation of ML scoring models (CTR, CVR, RoAS) integral to core bidding logic.
• Architect model strategies for complex solutions integrating user, product, and placement signals for high-throughput and low-latency environments.
• Partner with engineering and business stakeholders to translate goals into measurable modeling outcomes and technical roadmaps.
• Provide technical leadership and quality assurance for Data Science workstreams to ensure alignment with production standards.

Candidates must be EU citizens.