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.