Senior C#/.NET Developer (Wisej.NET)

Vallettasoftware - custom mobile/web software developer in the US and Europe. Our teams implement IT projects of varying complexity, including website and mobile app development, enterprise systems, and solutions based on artificial intelligence and machine learning (AI/ML).

We are proud to be named as one of the Top 10 Software Development Companies in Q2 2026 by 50Pros|Discover top agencies.

Our thorough approach to every project and deep understanding of Client's needs allow us to manage the outstanding quality.

About the Role

We are looking for a Senior C#/.NET Developer to take over and continue the development of an existing web-based business application built with Wisej.NET.

You will quickly take ownership of the codebase, implement new features, maintain existing functionality, and collaborate effectively in an international, distributed team.

Take over and continue development of an existing application built with Wisej.NET and C#.

Analyze and understand the current architecture and implementation.

Implement new features and enhancements according to business requirements.

Maintain and improve existing functionality.

Troubleshoot and resolve application issues and defects.

Collaborate with project stakeholders and distributed development team members.

Participate in knowledge transfer and ensure smooth project continuity.

Contribute to code quality, performance optimization, and technical documentation.

Requirements

Must-Have

✅ 5+ years of commercial experience with C# and .NET.

✅ Commercial experience with Wisej.NET (non-negotiable).

✅ Experience with ASP.NET, WinForms, or similar Microsoft technologies.

✅ Experience developing and maintaining web-based business applications.

✅ Strong object-oriented design and software engineering fundamentals.

✅ Ability to quickly learn existing frameworks and codebases.

✅ Experience with Git or similar source-control systems.

✅ Strong debugging, analytical, and problem-solving skills.

✅ Good communication skills in an international environment.

✅ English B2 or higher.

Nice-to-Have

🇩🇪 German language proficiency (preferred but not mandatory).

Experience taking over or maintaining legacy applications.

Experience in customer-facing projects or long-term product development environments.

Why Join

Work on a long-term product with real business impact.

International, distributed team with a collaborative culture.

Opportunity to take ownership of a mature application.

Flexible working conditions and remote work.