Umbraco is an open source, MIT-Licensed .NET content management system. Initially created by Danish developer Niels Hartvig in 2000 as a hobby project, Umbraco was released as open source in 2004 and has since been developed and maintained continuously by a core team made up of paid Umbraco employees and community members.

Developers using Umbraco can benefit from it's mature codebase, high degree of customisability, and large, friendly community. Contrary to other CMS systems, Umbraco does not constrain a developer to a "theme" or "plugin" based workflow. Umbraco instead provides a rich API on top of ASP.NET MVC, making existing .NET web developers feel at home when writing custom Umbraco solutions.

Editors using Umbraco can benefit from the intuitive "backoffice", a mobile-responsive AngularJS app which makes content-writing and admin tasks easy, and from the large amount of editor-focused documentation available including umbraco.tv.