SiberianCMS is an Open-Source web-based software to create mobile applications for Android and IOS using easy to use interface. No coding knowledge is required to create your own mobile applications for iOS and Android. It can also create Webapp, which is accessible using web browsers.
You can get it from
Source code for Siberian Single App Edition (SAE), free and open-source app builder available on Github. It is created in PHP using Zend Framework.