Senior Python Backend Engineer (MFA & Network Authentication)

Quick Facts

• Role: Senior Python Backend Engineer (MFA & Network Authentication)

• Focus: Backend development for network authentication and security logging

• Languages: Python primarily; some components may be in Go or Rust

• Work model: Full-time onsite in Kraków or Zielona Góra (employment contract) OR fully remote from anywhere in Poland (B2B)

• Language: Polish in daily team work

Description

You will take technical ownership of network authentication products, including an Authentication Proxy (RADIUS/LDAP + MFA) and a Log Sync service that exports audit/authentication activity logs to SIEM. The next generation must remain fast, secure, and easy to maintain at high scale, both in customer networks and in the cloud. The position is backend-only; no frontend experience is required.

Responsibilities

• Technically own the architecture, code quality, and releases for Authentication Proxy and Log Sync
• Design and implement RADIUS/LDAP protocol features (authentication modes, proxying, RadSec)
• Build horizontally scalable, highly available services for security-critical authentication traffic
• Choose the right technology per component and guide migrations where appropriate (Python, Go, Rust)
• Integrate with Active Directory, OpenLDAP, FreeIPA, Google Secure LDAP, Microsoft Entra ID, and other RADIUS servers
• Design reliable SIEM log delivery with checkpoints, retry mechanisms, and clear delivery guarantees
• Assess and improve security of protocol handling; perform threat modeling for new functionality (e.g., protection against Blast-RADIUS)
• Profile and improve performance, concurrency, and resource usage
• Define observability standards (structured logging, metrics, tracing, diagnostics)
• Set standards for building/packaging/releasing for Linux, Windows Server, and containers
• Define and standardize AI coding agent workflows in the team (e.g., CLAUDE.md, custom commands, automated code review)
• Perform code reviews and mentor junior engineers
• Collaborate with product managers, QA, support, and cybersecurity specialists

Benefits

• Private medical care
• MultiSport card
• Online courses and potential co-funding for certifications