We are supporting a major Belgian utilities organisation on a range of business-critical digital and system modernisation initiatives. For a long-term programme, we are looking for a strong .NET Fullstack Developer with proven WPF expertise to help evolve and maintain operator-facing and internal platforms.
This role requires someone who is genuinely comfortable building rich desktop applications in WPF, alongside solid backend development in .NET.
Logistics
* Role: Freelance .NET Fullstack Developer (WPF Focus)
* Contract: 12–24 months
* Location: Brussels (Hybrid – 2 days/week on-site)
* Languages: English + French or Dutch
* Start Date: ASAP / Flexible
* Rate: Competitive & negotiable
Responsibilities
* Design, develop, and maintain applications using .NET / C#
* Build and enhance rich desktop solutions using WPF (Windows Presentation Foundation)
* Contribute to both new development and modernisation of existing systems
* Translate complex business and operational requirements into scalable technical solutions
* Develop and maintain backend services and APIs
* Ensure clean architecture, code quality, and maintainability
* Participate in Agile ceremonies, code reviews, and technical discussions
* Collaborate with cross-functional teams to deliver reliable, high-performance solutions
Required Skills
* 5+ years of experience as a .NET Developer
* Strong expertise in C# and the .NET ecosystem
* Proven, hands-on experience with WPF (essential)
* Experience building fullstack solutions (desktop frontend + backend services)
* Solid knowledge of REST APIs and relational databases
* Experience with Git-based workflows and CI/CD environments
* Comfortable working autonomously within Agile/Scrum teams
* Experience on large, business-critical systems
Nice to Have
* Experience in the utilities or energy sector
* Exposure to legacy system modernisation projects
* Knowledge of Azure or cloud environments
* Familiarity with enterprise-scale architecture and performance considerations
If you're a strong .NET developer with deep WPF experience looking for a long-term freelance engagement within a high-impact utilities' environment, we'd be happy to discuss further.