You will play a key role in the design, development, and evolution of robust software solutions built on Microsoft technologies. As a senior developer, you combine strong hands-on expertise with a quality mindset, contributing actively to implementation while supporting the technical maturity of the team.
You work closely with architects, analysts, and fellow developers to translate business needs into secure, scalable, and maintainable applications with real societal impact.
What you'll do
* Design, develop, and maintain software components using modern .NET technologies, including both .NET Framework and .NET Core.
* Translate functional requirements into well-structured technical solutions in collaboration with analysts and architects.
* Contribute to the design of scalable and maintainable architectures, aligned with established architectural standards.
* Actively participate in coding activities, including feature development, refactoring, and bug fixing.
* Perform code reviews and promote best practices related to code quality, performance, security, and maintainability.
* Support and mentor less experienced developers through technical coaching and knowledge sharing.
* Ensure applications meet high standards for reliability, performance, and security.
* Continuously analyze and optimize system performance.
* Evaluate new technologies and frameworks and propose improvements aligned with business and technical objectives.
What are we looking for?
* You have solid experience as a
Senior .NET Developer
in complex application environments.
* You are highly proficient in
C# and .NET (Core and modern versions)
and have hands-on experience building
ASP.NET Core Web APIs
.
* You have experience implementing
authentication and authorization mechanisms
, including
JWT, OpenID Connect, and claims-based security
.
* You are comfortable developing user interfaces using
Blazor
and MVC patterns where appropriate.
* You have strong experience with
Entity Framework Core
and relational databases, particularly
SQL Server
.
* You design and consume
RESTful APIs
, and document them using
Swagger / OpenAPI
.
* You apply
unit and integration testing
consistently to ensure application quality and long-term maintainability.
* You communicate effectively in
Dutch, French, and English
, and collaborate well within multidisciplinary teams.
What do we offer?
Location: Brussels (on-site)
Start date: January 2026
Duration: Until end of 2026
Contract: Freelance or Permanent