Java software developer Jobs in Düsseldorf

WHO WE ARE Etinars is a values-focused company with multi-year experience, specialised in the recruitment of professionals for niche markets, managing the full life-cycle of specialist and executive-level hires. At Etinars, we genuinely care about who you are and what you need. We place great emphasis on fostering robust, enduring connections built upon trust and transparency. Our approach ensures a swift journey, leading you hand in hand towards signing your next career step. WHAT WE ARE LOOKING FOR .NET/Python Software Developer | Energy Sector Join our client large international organisation active in the energy sector, contributing to real-time energy management & balancing and solutions that support the energy transition. You will work on real-time software products that help balance the electric grid and connect physical assets (e.g., batteries, renewable parks) to internal systems for forecasting and optimisation. In this role, you will work 2 days per week onsite in Brussels and the rest remotely, collaborating closely with multidisciplinary stakeholders and technical teams in an international environment. We are looking for a Software Developer with 3+ years of experience, strong skills in .NET or Python (interest in both), and exposure to event-driven architectures, distributed systems, and Kubernetes. For this role, relocation to Brussels (Belgium) is mandatory for candidates living far from the area, or the ability to commute regularly. Languages required: English (B2+) due to daily interactions with teams and stakeholders. French is a plus. YOUR TASKS Clarify needs with functional analysts and domain experts. Produce technical designs and architectural proposals documented with diagrams, including APIs, services, and interactions. Break down solutions into agile progressive upgrades. Implement builds and associated testing and maintenance tools. Develop back-end services and APIs. Write tests in collaboration with business colleagues; contribute to production validation. Create documentation and user manuals; provide user assistance and support. Monitor systems and provide L2 support, incident resolution, troubleshooting and root-cause analysis for recurring incidents. YOUR SKILLS AND EXPERIENCE Must-have 3+ years of software engineering experience. Proficiency in .NET or Python (incl. async programming and performance-oriented design), with interest in both. Hands-on experience with event-driven architectures and distributed systems (e.g., Kafka, Azure Event Hub, or MQTT). Hands-on experience with Kubernetes in production (deployments, autoscaling). Experience with stateful systems such as Redis (caching use cases). Strong testing culture: unit tests, integration tests, production validation. Familiarity with Agile practices. Nice-to-have Exposure to Azure and Infrastructure as Code (e.g., Bicep). Familiarity with parts of the stack: AKS / Azure Functions, Azure Service Bus, PostgreSQL, GitHub Actions / CI/CD. Experience with Scala or Rust is a plus. Master’s degree (polytechnic engineering) is a strong plus. Soft skills Proactive mindset, collaborative spirit, willingness to support team delivery. Ability to break down complex problems and propose pragmatic, scalable solutions. Ownership, accountability, empathy and humility. Strong communication skills (written and oral). EXTRA INFORMATION Location: Brussels, Belgium (relocation mandatory if living far / or ability to commute regularly) Work model: Hybrid - 2 days onsite / 3 days remote Start: ASAP, ideally by 02/03/2026 Contract duration: 1 year, extendable by +1 +1 years (max 3 years) Contract type: Freelance Languages: English (B2+), French is a plus Daily rate range: €475–€500/day (all-in; depending on profile/experience, within the project budget cap) Eligibility: EU Citizens, or Non-EU citizens already based in the EU with a valid work permit Once we receive your CV, we will take the time to evaluate it carefully. Should there be a match for this or any other position at Etinars, we will be in touch. Etinars is committed to supporting a Diverse and Inclusive Community. If you meet the minimum criteria for the job, you will be given the opportunity to demonstrate your abilities at an interview.