Python Developer

Python & SQL Data Engineer (Junior & Senior)

Location: Warsaw, Poland (Hybrid, weekly office visits)

Contract Type: B2B Contract

Start Date: ASAP

Rate: 20-25 euros per hour

About the Project

We are expanding our data engineering team to build and maintain high-scale transaction fee calculation and portfolio management engines supporting platforms managing over one trillion euros in assets. You will design, develop, and optimize data processing workflows handling large-scale datasets, ensuring peak operational performance, database resilience, and processing speed.

Key Responsibilities

• Build and maintain robust data pipelines and automated processing services using Python and relational database engines
• For Senior engineers: lead advanced SQL query optimization, indexing strategies, execution plan tuning, and performance profiling across tables containing millions of rows
• Integrate data frameworks to streamline ingestion, transformations, and transaction fee logic
• Collaborate closely with distributed engineering and infrastructure teams across Europe in a hybrid structure

Requirements

• Junior Level: 1 to 2 years of commercial software or data engineering experience with strong Python and SQL skills
• Senior Level: 3 to 5 years of commercial experience with expert-level SQL and deep knowledge of performance tuning at enterprise scale
• Bachelor of Science (BSc / Inżynier) degree in Computer Science, Software Engineering, or a related technical discipline
• Hands-on experience with relational databases, with PostgreSQL strongly preferred
• Familiarity with high-throughput Python data libraries; experience with Polars is a distinct advantage
• Strong communication skills in English (B1/B2 minimum for Junior, fluent for Senior)