Jan Fietz
Freelance software developer & consultant. Backend, cloud-native architectures, renewable energy.
Services
From prototype to production-ready product — backend, APIs and cloud architecture from a single source.
Senior reinforcement for ongoing projects — embedded, productive, and focused on backend, APIs and infrastructure.
Clear answers on architecture, process and automation questions — before they get expensive.
Backend solutions for direct marketing, asset monitoring and industrial control systems — from wind or solar plant to market interface.
How I work
AI tools are part of the workshop today. Used where they help — eliminate boilerplate, speed up tests, sharpen code reviews. The result: two to three times faster delivery at the same quality, with tests and clean architecture.
Wherever it makes sense, open components are used. PostgreSQL, Prometheus, Kubernetes, GitLab CI. Not a religion — better inspectability, longer lifespan, fewer license traps.
Architectural decisions are made so that migration stays possible. Container-based workloads, standard protocols, clean separation between business logic and cloud adapters. You should not be chained to a vendor because it was easy for me.
Linux is home, not specialist knowledge. From the shell to container runtimes, from systemd to kernel tuning. That makes the difference when systems are under load or when a grown setup needs to be analysed.
Work
Quantec Networks, Quantec Systems, Scada International, Opoura GmbH · 2011 - 2026
15 years of responsibility for a SCADA middleware with over 8,000 connected assets at 30+ customers across Europe and the US — from protocol layer to cloud-native deployment.
Role: Developer → Senior → Team lead · Technical advisory · Third-level support
Quantec Networks, Quantec Systems, Scada International, Opoura GmbH · ~10 years
Bidirectional extension of the data gateway: 10 Hz closed-loop active and reactive power control, multi-protocol, in production at thousands of plants and connected to leading TSOs and direct marketers.
Role: Development and architecture of the control and interface layer
Quantec Systems, Scada International, Opoura GmbH · Live in DK, SE, PL
Stand-alone product for the European balancing reserve market: primary, secondary and tertiary reserve including Nordic variants — for wind, solar, BESS, hybrid and controllable loads.
Role: Market and control interfaces · cross-product integration coordination
Quantec Systems, Scada International, Opoura GmbH · Greenfield to production
Greenfield platform for 24/7 operations: roughly 7,000 assets and controllers in real-time monitoring, ~50 concurrent operators, multi-cloud and on-premises via the same deployment pipeline.
Role: Architecture and initial implementation · building and leading the development team · product management
Contact
Tell me about your project — I'll get back to you.