The Microsoft platform is the most pervasive platform in business circles for building web applications. For companies professing to develop solutions built on the .NET platform, look for a Microsoft Certification. The web-related elements of the .NET platform are collectively known as ASP.NET. While the .NET platform is most often found running on the Microsoft server platform (under the web server IIS), an open source compiler and runtime environment (called “Mono”) is available which will allow .NET code to run on most any platform.
Microsoft offers a wide variety of certifications for both individual developers as well as companies offering expertise on its .NET platform and related family of Microsoft technologies.