Kapsules was a freeware desktop widget engine for Windows. It made use of the Windows Scripting Technology, allowing widget designers to use any scripting language that has an ActiveScript engine. Those widgets were then made available on Kapsules' website. As of December 2005[update], widgets are available in eight different scripting languages. Kapsules is reliant on the .NET Framework. All versions of Kapsules before and including version 0.9.9.0 have targeted version 1.1 of .NET, and all later versions target version 2.0.
As mentioned above, widgets could be written in any language for which there is an ActiveScript engine. Kapsules also supports .NET scripting languages. This flexibility allows widget designers to use and interface with a much larger codebase, enabling them to interface with a wider variety of existing software components. Widgets have been written in Python, PHP, JScript, JScript.NET, VBScript, VB.NET, Ruby and Perl.
On or around November 9, 2006, the Kapsules website was updated with a single page stating that the site had been hacked. It also said that the developers were "busy" working on an updated version of the application and the website. No updates have been made since the announcement. The project website and its domain have since been abandoned.