Senior/Lead Data Scientist

N-iX; Kraków; Hybrid; PLN 180,000 - 280,000; Full time

Benefits offered by this job

Flexible working format

Competitive salary and compensation

Mentorship program and tech talks

Centers of excellence and knowledge分享

Job summary

N-iX is seeking a Senior Data Scientist to shape AI and ML systems across Europe and Canada, building and operating production-grade ML and GenAI solutions. You will collaborate with product and engineering leaders, influence technical direction, and mentor other data scientists to deliver impactful outcomes.

The role combines hands-on development with strategic guidance, operating across multiple markets, with a flexible remote/office-based format.

Qualifications

• 5+ years of experience building and owning production ML systems end-to-end in a real-world environment.
• Advanced degree in Computer Science, Engineering, Mathematics, or a comparable field.
• Strong hands-on expertise in Python and modern ML frameworks(PyTorch), with the ability to ship, operate, and evolve ML systems in production.
• Solid experience with AWS and MLOps practices, including deployment and monitoring at scale.
• Experience with MLflow and GenAI/LLMs in production contexts, understanding trade-offs and limitations.
• Ability to influence technical decisions through collaboration and sound judgment.
• Experience mentoring junior data scientists and providing technical feedback.
• Excellent verbal and written English skills.

Responsibilities

• Own ML and GenAI systems end-to-end in production, including framing, design, deployment, monitoring, and improvement.
• Make architectural and methodological decisions for ML systems on AWS, balancing robustness and cost.
• Collaborate with Product, Engineering, and Business leaders to turn problems into ML-enabled solutions with clear outcomes.
• Operate ML systems deployed across multiple countries and markets, considering data and regulatory differences.
• Mentor other data scientists through hands-on guidance and code reviews.
• Raise the bar for engineering practices across the Data Science organization.

Skills

Python

PyTorch

GenAI/LLMs

MLOps

English communication

Education

Advanced degree in Computer Science

Advanced degree in Engineering

Advanced degree in Mathematics

Tools

AWS

Grafana

MLflow

Job description

Our client is a leading European online car marketplace, connecting car buyers and sellers across the continent. The platform serves over 30 million monthly users and operates across 18 countries, making it one of the largest and most trusted digital marketplaces for vehicles in Europe.

About the role

As a Senior Data Scientist, you will be a key contributor within the client's global Data Science organization, shaping the AI and machine learning systems that sit at the core of marketplace platforms across Europe and Canada. You will design, build, and operate machine learning and GenAI systems that run in production and matter to the business - working on complex, ambiguous problems, exercising strong technical judgment, and taking responsibility for outcomes, not just models.

While this is a hands-on role, you will also influence technical direction, raise the bar for engineering practices, and enable other data scientists and engineers to succeed.

Responsibilities:

• Own ML and GenAI systems end-to-end in production, including problem framing, system design, deployment, monitoring, and continuous improvement.
• Make sound architectural and methodological decisions for ML systems on AWS, balancing robustness, observability, cost, and long-term maintainability.
• Partner closely with Product, Engineering, and Business leaders to turn ambiguous problems into ML-enabled product solutions with clear outcomes.
• Operate and evolve ML systems deployed across multiple countries and markets, accounting for differences in data distributions, regulations, and constraints.
• Mentor other data scientists through hands-on technical guidance, design reviews, and shared ownership of systems.
• Raise the bar for engineering practices across the Data Science organization and influence technical direction beyond your own projects.

Requirements:

• 5+ years of experience building and owning production ML systems end-to-end in a real-world environment.
• Advanced degree in Computer Science, Engineering, Mathematics, or a comparable field.
• Strong hands-on expertise in Python and modern ML frameworks(PyTorch), with the ability to ship, operate, and evolve ML systems in production.
• Solid experience with AWS(EC2, S3, Permission setup, security services) and MLOps practices(Grafana), including deployment, monitoring, and operating ML systems at scale.
• Expertise with MLflow(knowledge of 3-base model is a must)Practical experience applying GenAI / LLMs in applied or production contexts, with a clear understanding of trade-offs and limitations.
• Ability to influence technical decisions through clear judgment and collaboration, not formal authority.
• Experience supporting and guiding more junior data scientists through hands-on collaboration, code reviews, and technical feedback.Strong sense of ownership and accountability for outcomes, with a pragmatic approach to trade-offs and delivery.
• Excellent verbal and written English skills.

We offer*:

• Flexible working format - remote, office-based or flexible
• A competitive salary and good compensation package
• Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)
• Active tech communities with regular knowledge sharing