Web Platform Installer

Web Platform Installer (Web PI) was a freeware, closed-source package management system that installs non-commercial development tools and their dependencies that are part of Microsoft Web Platform, including:
 * Internet Information Services
 * WebMatrix
 * Visual Web Developer Express Edition
 * Microsoft SQL Server Express Edition
 * .NET Framework
 * Silverlight Tools for Visual Studio
 * PHP
 * WordPress
 * Umbraco
 * Drupal
 * Joomla!
 * Orchard

The ability to install third-party software was added in version 2.0, released September 24, 2009. , Web PI can install 82 titles. Web PI 2.0's options are populated dynamically at runtime from Microsoft's servers, allowing installation options to be updated without the need to download newer versions of the Web PI itself.

On July 7, 2010, Microsoft announced Web PI 3 which includes WebMatrix, a new set of integrated tools for web development. Web PI 3 installs additional tools for web development including IIS Developer Express, SQL Server Compact and DotNetNuke.

Web PI features an offline mode where products can be downloaded to a local cache on a machine where internet access is available and then use these cached files on a different machine later. However, Web PI is still not usable in environments where Internet connectivity and local administrator privileges are mutually exclusive (i.e. a given process can either authenticate through a transparent proxy, or can have High or System integrity level, but not both).

The Microsoft Web Platform Installer (WebPI) has been retired since July 1, 2022.