Senior Software Engineer (Backend)

TL;DR

Senior Backend Engineer (Python): Design and build core systems that power real-world energy processes, from billing to market communication with an accent on data modeling, asynchronous processing, and distributed systems. Focus on evolving legacy systems toward modern architectures and improving engineering practices, including AI-assisted workflows.

Location: Modern office in Berlin Kreuzberg. Flexible hours and hybrid work setup.

Company

Lumenaza is a green-tech company building software for the decentralized energy world, enabling energy providers to manage billing, market communication, and energy data to support renewable energy business models at scale.

What you will do

• Build and own core backend systems for billing, tariff models, and energy market processes.
• Shape system architecture, ensuring maintainability, scalability, and correctness across the full lifecycle.
• Solve complex technical challenges involving data modeling, asynchronous processing, and distributed systems.
• Collaborate with Product, Frontend, and DevOps to deliver cloud-based solutions and improve our platform.
• Drive improvement and innovation by bringing in new ideas and exploring modern development approaches.
• Modernize existing systems by helping evolve and migrate legacy systems toward modern architectures.

Requirements

• 5+ years of backend development experience.
• Strong Python and Django expertise.
• Experience designing and building REST APIs.
• Experience with distributed systems / microservices.
• Solid understanding of databases (PostgreSQL).
• Experience with Docker and CI/CD workflows.
• Strong communication skills in English.

Nice to have

• Experience with FastAPI, Pydantic, or Django Ninja.
• Knowledge of Celery or similar async tools.
• Experience integrating external systems (e.g. ERP, APIs).
• Familiarity with React / TypeScript.
• Interest in energy markets or regulated domains.

Culture & Benefits

• Impact: Build software that directly enables renewable energy business models.
• Ownership: Work on complex, meaningful systems with real-world impact.
• Growth: Structured onboarding and continuous learning.
• Flexibility: Flexible hours and hybrid work setup.
• Benefits: Competitive compensation, Deutschlandticket.
• We strongly encourage applications from underrepresented groups in tech and are committed to building an inclusive environment.