Senior Software Engineer (Backend)

As a Senior Backend Engineer, you will design and build core systems that power real-world energy processes - from billing to market communication.

You take ownership of complex domains, contribute to architectural decisions, and help evolve both our systems and engineering practices.

What You’ll Do

• Build and own core backend systems Design and implement scalable solutions for billing, tariff models, and energy market processes.

• Shape system architecture Work across the full lifecycle - from design to deployment - ensuring maintainability, scalability, and correctness.

• Solve complex technical challenges Develop robust solutions involving data modeling, asynchronous processing, and distributed systems.

• Collaborate across disciplines Work closely with Product, Frontend, and DevOps to deliver cloud-based solutions and improve our platform.

• Drive improvement and innovation Bring in new ideas, improve engineering practices, and explore modern development approaches, including AI-assisted workflows.

• Modernize existing systems Help evolve and migrate legacy systems toward modern architectures.

• 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

Our Tech Stack

• Python, Django, Django REST Framework
• PostgreSQL, Redis
• Celery (async processing)
• Docker, Kubernetes
• GitLab CI/CD
• Robot Framework (testing)
• React (frontend)

We deploy continuously to Kubernetes and work with distributed systems handling complex, business-critical data.

• 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
• Location: Modern office in Berlin Kreuzberg

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

We are driven by a clear mission: accelerating the transition to a sustainable energy system. At the same time, we value diversity, collaboration, and continuous learning., Lumenaza GmbH, through its brand Lumenaza.Community, is a leading provider of direct marketing for small-scale installations and a supplier of electricity for household tariffs ranging from fixed to dynamic contracts. The Lumenaza Community represents green, decentralized electricity generation.

Since 2013, Lumenaza GmbH has also been supporting major energy supply companies such as EnBW and E.ON as a software and service provider, offering innovative solutions in billing, market communication, and virtual power plants.