Freelance Senior Fullstack .NET Developer

Job Title: Freelance Senior Fullstack .NET Developer

Location: Brussels, Belgium

Start Date: ASAP

Contract Type: Freelance

Work setup: 2 days/week on-site, 3 days remote

About the Role:

We are seeking a seasoned and solution-oriented Fullstack .NET Developer to support a key client in Brussels. This role is ideal for someone who thrives on modernizing legacy systems and driving scalable transformation. You will be instrumental in translating business requirements into innovative technical solutions, ensuring seamless interaction between new and existing systems. The software you’ll work on is central to the client's ecosystem, enabling interoperability across multiple products.

Key Responsibilities:

• Design and implement scalable, standardized solutions based on new business needs
• Ensure smooth integration with legacy systems and support gradual migration
• Create and maintain technical documentation and dependency diagrams
• Collaborate closely with stakeholders to align technical delivery with business goals
• Quickly understand complex business logic and technical constraints
• Contribute to the modernization of core systems impacting the entire product suite

Your Profile:

• Minimum 5 years of experience with .NET and Microsoft SQL Server
• Experience with PowerBuilder
• Strong ability to produce clear technical documentation
• Excellent communication and stakeholder management skills
• Proven ability to translate business needs into sustainable technical solutions
• Fluent in English; good understanding of French and/or Dutch is a plus

Nice-to-Have:

• Experience with Azure DevOps
• Familiarity with Azure Cloud
• Exposure to Kubernetes