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Salary: EUR 5,000 - 6,500 / monthly
DeWarmte designs and manufactures smart, affordable heat pumps that help homes transition away from gas. The company builds hardware, software, and services in-house, meaning software quality directly impacts product performance in customers' homes.
As a Backend Developer, you'll build and improve the Django platform that powers DeWarmte's web application, customer app, employee app, and connections to heat pumps, data systems, and external smart-home partners like Homey and Home Assistant. You'll spend most of your time writing production code: improving reliability and performance, building new functionality, and helping the platform scale with a rapidly growing customer base and installed fleet.
Key responsibilities include:
- Develop and maintain the Django backend serving web, mobile, and internal applications
- Design, build, test, and deploy new APIs, services, and business logic covering customer journeys, heat pump control, and service workflows
- Improve performance, stability, security, and data integrity across the platform
- Diagnose and fix issues spanning backend, data platform, and field devices
- Scale databases, background processing, and infrastructure to support growth
- Define clear, documented interfaces between device software, cloud services, and dependent products
- Implement automated testing, observability, monitoring, and release practices
- Use AI tools to support design, coding, testing, and documentation while maintaining production standards
- Document implicit knowledge, design maintainable systems, and participate in code reviews
- Collaborate across product, web, apps, hardware, controls, data, and service teams
Success in the first few months means understanding the existing backend architecture, independently maintaining and releasing changes, identifying technical risks, and visibly improving monitoring and documentation. As the role develops, you'll ship new functionality predictably and safely, scale the platform smoothly, detect and resolve incidents systematically, and help the team use AI tools responsibly.
Requirements:
- Solid hands-on backend engineering experience with ownership of production systems
- Deep Python and Django expertise, including Django ORM and REST APIs (e.g., Django REST Framework)
- Strong relational database knowledge (e.g., PostgreSQL): data modeling, query optimization, migrations
- Experience with background processing, queues, event streaming, and external system integration
- Track record of taking functionality from design through implementation, testing, and deployment
- Strong engineering fundamentals: version control, automated testing, CI/CD, observability, incident handling
- Practical experience using AI coding tools and understanding their value and limitations
- Ability to bring clarity to evolving systems and processes
- Useful but not essential: IoT, connected devices, telemetry, time-series data (Kafka, InfluxDB), or cloud infrastructure experience
