51Aspx is a source-code marketplace for network applications and .NET/Asp.net projects, positioned as a code trading and download directory. The site includes featured, free, shared and commercial source code, with filters for authorization type, development language, B/S or C/S source type, database, category, user rating and download rankings. It also supports source code upload.

Access generally requires registration or login, and projects may be free or paid. Deployment requirements vary by source package and may depend on .NET, Visual Studio, Spring Boot/Vue, SQL Server, MySQL and other environments. The site is mainly in Chinese, so selection should verify each item’s license, dependencies, regional availability and compliance requirements.