Senior Data Science Lead - Hands-On & Client-Facing

Sii Poland; Wrocław; On-site; PLN 250,000 - 390,000; Full time

Benefits offered by this job

Great Place to Work

Solid financial situation

Contracts with the biggest brands

Centre of internal trainings

Many experts you can learn from

Open and accessible management team

Profit sharing

Passion Sponsorship program

Regular integration events and trips

Comfortable and well-equipped offices

MySii app

Medical care

Job summary

Sii Poland is seeking a technical lead to own the end-to-end direction of data science engagements, framing problems for clients, selecting modeling approaches, and validating results. You'll mentor a team of data scientists, review work, and still contribute production-grade Python.

You'll bridge business impact with technical decisions across modern cloud platforms and AI tooling. This hands-on role emphasizes leadership as much as coding, with opportunities to shape standards, governance, and

Qualifications

• At least 6 years in data science with a track record of models shipped to production.
• Minimum of 2 years leading or mentoring other data scientists.
• Strong Python skills across the standard data stack.

Responsibilities

• Own the technical direction of data science engagements: solution design, modeling approach, validation strategy, and delivery quality.
• Lead and mentor a team of data scientists - code reviews, methodology reviews, career development, and raising the bar on what "done" means.
• Stay hands-on: prototype approaches, unblock hard modeling problems, and contribute production-grade Python where it matters most.
• Translate client business problems into scoped, estimable data science workstreams, and push back when the problem doesn't need a model.
• Set and enforce engineering standards for reproducibility, experiment tracking, testing, and documentation.
• Guide platform decisions and delivery across cloud/data ecosystems - Microsoft Fabric, Palantir Foundry, Databricks, Snowflake, and native Azure/AWS/GCP services.
• Work with AI Architects, data engineers, and client stakeholders to align technical decisions with business outcomes.
• Represent the team in front of clients: present results, defend methodology, and manage technical expectations

Skills

Python

Data science

Mentoring

Communication

Cloud platforms

English

Polish

Tools

pandas

NumPy

scikit-learn

XGBoost

Azure ML

SageMaker

Vertex AI

Snowpark ML

Databricks MLflow

Foundry Code Workspaces

Job description

Sii Poland is seeking a technical lead to own the end-to-end direction of data science engagements, framing problems for clients, selecting modeling approaches, and validating results. You'll mentor a team of data scientists, review work, and still contribute production-grade Python.

You'll bridge business impact with technical decisions across modern cloud platforms and AI tooling. This hands-on role emphasizes leadership as much as coding, with opportunities to shape standards, governance, and