The friendliest, most flexible and fastest growing ASP.NET CMS used by more than 390,000 websites worldwide: https://umbraco.com
Umbraco is a free open source Content Management System built on the ASP.NET platform. Our mission is to help you deliver delightful digital experiences by making Umbraco friendly, simpler and social.
The easiest way to get started is to run build/build.bat which will build both the backoffice (also known as "Belle") and the Umbraco core. You can then easily start debugging from Visual Studio, or if you need to debug Belle you can run gulp dev in src\Umbraco.Web.UI.Client.
Note that you can always download a nightly build so you don't have to build the code yourself.
For the first time on the Microsoft platform, there is a free user and developer friendly CMS that makes it quick and easy to create websites - or a breeze to build complex web applications. Umbraco has award-winning integration capabilities and supports ASP.NET MVC or Web Forms, including User and Custom Controls, out of the box.
Umbraco is not only loved by developers, but is a content editors dream. Enjoy intuitive editing tools, media management, responsive views and approval workflows to send your content live.
Used by more than 350,000 active websites including Carlsberg, Segway, Amazon and Heinz and The Official ASP.NET and IIS.NET website from Microsoft (https://asp.net / https://iis.net), you can be sure that the technology is proven, stable and scales. Backed by the team at Umbraco HQ, and supported by a dedicated community of over 200,000 craftspeople globally, you can trust that Umbraco is a safe choice and is here to stay.
To view more examples, please visit https://umbraco.com/why-umbraco/#caseStudies
As an Open Source platform, Umbraco is more than just a CMS. We are transparent with our roadmap for future versions, our incremental sprint planning notes are publicly accessible and community contributions and packages are available for all to use.
The downloadable Umbraco releases live at https://our.umbraco.org/download.
Peer-to-peer support is available 24/7 at the community forum on https://our.umbraco.org.
Umbraco is contribution focused and community driven. If you want to contribute back to Umbraco please check out our guide to contributing.
Another way you can contribute to Umbraco is by providing issue reports. For information on how to submit an issue report refer to our online guide for reporting issues.
To view existing issues, please visit http://issues.umbraco.org.