You cannot display key artwork above the top edge of a custom keyboard’s primary view the same way Apple does when you tap and hold a key in the top view.

If an app provides an editing menu interface, the keyboard has no access to it.

Closely related to the above point, editing menu options i.e.

Text selection is under the control of the app that is using the keyboard.

Input dictation isn’t possible for a custom keyboard since, like all extensions in iOS 8, it has no access to the device microphone.

When the user types in any of these text input objects, the system temporarily replaces your custom keyboard with the system keyboard, and on typing in a non-secure or non-phone pad object, your keyboard resumes. These include the secure text input objects (any object that has its secureText property set to YES) and phone pad objects (any object that has a keyboard type trait of UIKeyboardTypePhonePad or UIKeyboardTypeNamePhonePad).

A Custom Keyboard cannot be used to type into certain text input objects.

You can check the Implementing an iOS Settings Bundle guide for more on this. However you can provide your own settings bundle that can be displayed in Settings.app.

Custom keyboards don’t have access to most of the general keyboard settings in the Settings app such as Auto-capitalization, Enable Caps Lock or dictionary reset.

There are some system keyboard features that are unavailable to custom keyboards.

Appropriate layout and features based on keyboard type trait for example presenting appropriate keys for easy email input when the user switches to an email field.

Multistage input for ideographic languages.These are not requirements for creating custom keyboards, but just examples of what you could include in your keyboard to increase the chances of it being popular in a competitive market. Users have come to expect the following features from their keyboard. It doesn’t interrupt the user with requests or information.

The system keyboard is fast, responsive and capable.

Custom keyboard swift github