Official documentation
App Extension Programming Guide: Custom Keyboard
Apple, Apple Developer Documentation (archived), n.d.
Read the originalRead on October 17, 2026
- What it is
- Apple's archived developer guide to custom keyboard extensions on iOS. It sets out which text fields a third-party keyboard may type into, and when the system takes over the keyboard.
- How much weight it carries
- Official but archived, so it may describe older iOS versions. The rule on secure text fields is long-standing and matches how iOS behaves, but check Apple's current documentation for the version you run.
Facts taken from this source
- Apple says that when a user taps a secure text input object, such as a password field, the system temporarily replaces a custom keyboard with the system keyboard.
“When a user taps in a secure text input object, the system temporarily replaces your custom keyboard with the system keyboard.” (Custom keyboard restrictions)