Rhomobile’s open source mobile application framework Rhodes lets you quickly build native mobile applications for all smartphone operating systems: iPhone, BlackBerry, Windows Mobile, Symbian and Android. These are true native device applications (not mobile web apps) which work with synchronized local data and take advantage of device capabilities such as GPS, PIM contacts and camera.

It is licensed under GPLv3. So if the you are willing to open source your application, then you are compliant with that license and owe Rhomobile nothing. However, if you want to keep the application source code private then you need to purchase a commercial license from Rhomobile. The proposed licensing model is a percentage of the app proposed price.

The main shortcoming of the library is that it is currently unable to do anything with multimedia (audio and video). So it is great for any database-driven app with on-line synchronization, in fact the framework is optimized for interacting with transactional enterprise application backends. It is also designed to work with synced local data using a local database such as SQLite or DB40 and a generic backend synchronization framework such as RhoSync (another open source component available from Rhomobile).

It is available for iPhone, Research in Motion (Blackberry), Windows Mobile, Symbian and Android support has been recently added.

Basically, it takes the idea I had the moment the iPhone came out of getting a webserver and an interpreter into the device to a whole new level, by integrating those components into the compiled native application for all those platforms, along with some interface libraries such as IUI to make the app look and feel like a native app.

Rhodes takes much of its inspiration from web-oriented MVC style frameworks such as Ruby on Rails. However it has several simplifications and optimizations for the mobile scenario. Most of them are to keep the framework as lightweight as possible to be able to run on mobile devices with limited memory.

The main attractive of this framework is the ability to develop once and distribute on all App Stores for all these mobile platforms (iPhone, Blackberry, Windows Mobile, Symbian and Android).