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.
LogisticsRole: Freelance .NET Fullstack Developer (WPF Focus)Contract: 12–24 monthsLocation: Brussels (Hybrid – 2 days/week on-site)Languages: English + French or DutchStart Date: ASAP / FlexibleRate: Competitive & negotiable
ResponsibilitiesDesign, 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 systemsTranslate complex business and operational requirements into scalable technical solutionsDevelop and maintain backend services and APIsEnsure clean architecture, code quality, and maintainabilityParticipate in Agile ceremonies, code reviews, and technical discussionsCollaborate with cross-functional teams to deliver reliable, high-performance solutions
Required Skills5+ years of experience as a .NET DeveloperStrong expertise in C# and the .NET ecosystemProven, hands-on experience with WPF (essential)Experience building fullstack solutions (desktop frontend + backend services)Solid knowledge of REST APIs and relational databasesExperience with Git-based workflows and CI/CD environmentsComfortable working autonomously within Agile/Scrum teamsExperience on large, business-critical systems
Nice to HaveExperience in the utilities or energy sectorExposure to legacy system modernisation projectsKnowledge of Azure or cloud environmentsFamiliarity 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.