What is Cydia?

Cydia is a software installation app available for iOS devices (such as the iPhone or the iPad) which enables the user to download and run software not available through Apple. Cydia launched in 2008 and was the creation of developer Jay Freeman.

Cydia can only be installed on devices that have been 'jailbroken.' To 'jailbreak' an iOS device means that a program such as Pangu or evasi0n has been used to removed the limits on your iOS device which have been installed by Apple. This then allows the user to install customized apps which would otherwise have been blocked by the device's security and factory settings.

Apps offered in Cydia may have been rejected by Apple as they violate the company's terms for apps or are in direct competition with Apple’s own apps. Some of Cydia's apps allow users to do things Apple doesn’t want them to do.

What Can I Install Using Cydia That I Can't Get from Apple?

There are a great many apps and 'tweaks' (minor programming improvements) only available through Cydia that users believe to be essential; games, productivity and networking applications, even the look of your iOS device - the icons and wallpaper, for example - can be changed once Cydia has been run.

Apps available in Cydia otherwise unavailable include:

-  Syncing over WiFi; emulators for video game consoles; 

- removal of Apple’s restriction on iPhone or iPod touch video to connect it to TV; 

- allows you to create your own ringtones; modifying the OS’s basic interface; 

- downloading files directly to the iPhone, iPod touch, or iPad.

Once installed and launced, Cydia will present you with a 'store,' much like the Apple iStore, listing new applications for you to buy.

Here's a video tutorial on using Cydia: