Senior Software Engineer (Backend) (m/w/d)

This is us:
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.

Your tasks:
Your Role

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.

Your profile:
Core 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

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.

We offer you this:
• 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

We strongly encourage applications from underrepresented groups in tech and are committed to building an inclusive environment.