The Nokia Series 40 is a mobile device platform. It is considered as the world's most widely used mobile platform and is found in more than 100 million mobile devices. This is what makes the Nokia Series 40 platform so important apart from being able to provide a means to make even mass market mobile device users access to the Internet through such mobile gadgets.

The Nokia Series 40 makes use of a simpler operating system than other high end Nokia developed platforms which are based on the Symbian OS. A difference with the Nokia Series platform is that it doesn't provide support for add-on third party mobile applications as well as multi-tasking functions. But because of it simplified form, the Nokia Series 40 user interface is more responsive and performs faster than other Nokia mobile platforms.

The Nokia Series 40 continues to evolve and also allows developers of mobile applications with a means to reach a bigger number of mobile phone users. Since it is a widely used platform in the mass market, developers are keen to develop and make more applications for this platform because of its reach among mobile device users across the globe. And the Series 40 also is going through further development in order to offer better features that would help to eventually merge the differences between mobile and desktop product development.

For browsing on the web, the Nokia Series 40 offers support for WAP, XHTML and HTML browsing. Newer versions also offer support for CSS, Javascript and Ajax. This also allows developers to work with applications using the different languages that the Series 40 can support. The Series 40 platform has also gone into further development in order to improve the delivery of media content and applications through mobile devices. The newest edition of the Nokia Series 40 platform now supports the delivery of streaming audio and video through mobile networks.