ASP.NET Zero is a starting codebase and framework for building web applications. It provides multiple architecture options including ASP.NET Core + Angular, ASP.NET Core + MVC, .NET MAUI, and a Public Website. Key features include a modern UI and SOLID architecture starting codebase with full source code, common requirements like login, user management, settings, logging pre-built, rapid application development with built-in features and tooling, support for multi-tenancy, localisation, automated testing and more.