Senior Python Backend Engineer — Scalable REST APIs & AI

b3consultingpoland; Kraków; Hybrid; PLN 180,000 - 260,000; Full time

Benefits offered by this job

Health and sports benefits

Speed Coaching

Sports training

Team events

Development-focused meetups

Job summary

b3consultingpoland is seeking a Senior Python Engineer to join our Kraków-based team. You will design, build, and scale backend services in a SaaS setting, focusing on robust REST APIs and data-driven features for international collaboration.

You will work with product teams to translate requirements into reliable software, perform thorough testing, and mentor peers while leveraging AI-assisted tools for code reviews and innovation.

Qualifications

• Hands-on senior-level engineering experience building back-end systems.
• Strong Python fundamentals and Django development experience.
• Relational databases (PostgreSQL) with optimized queries and schema management.
• Experience architecting and delivering scalable REST APIs.
• Solid testing practices (unit/integration) focused on numerical/analytic logic.
• Comfort with applied statistics (regressions, distributions, p-values) and modeling.
• Daily use of AI coding assistants (Cursor, Copilot, Claude Code).
• Fluent written and spoken English for international collaboration.

Responsibilities

• Design, develop, and expand scalable backend services, modules, and REST APIs within a SaaS architecture.
• Implement, verify, and continuously test analytical and statistical algorithms to guarantee full correctness and output accuracy.
• Analyze business and technical requirements in close collaboration with product teams, engineering peers, and Tech Leads.
• Perform code reviews for other engineers — including solutions created with AI assistance — and provide mentorship to support team growth.
• Maintain system stability, execute data migrations, manage complex operations on large datasets, and handle infrastructure upgrades.
• Diagnose, analyze, and efficiently resolve technical issues and production bugs.
• Actively adopt AI developer tools in daily workflows and propose concepts for new AI-powered product features.

Skills

Python

Django

PostgreSQL

REST APIs

Unit & integration tests

Statistics

AI tools

English

Mentorship

Backend engineering

Tools

Cursor

GitHub Copilot

Claude Code

Job description

b3consultingpoland is seeking a Senior Python Engineer to join our Kraków-based team. You will design, build, and scale backend services in a SaaS setting, focusing on robust REST APIs and data-driven features for international collaboration.

You will work with product teams to translate requirements into reliable software, perform thorough testing, and mentor peers while leveraging AI-assisted tools for code reviews and innovation.