A new Fields API has been born again from the Metamorphosis Metadata UI/API project that started in late 2013. It’s hard to believe it’s been that long. It’s getting another, scaled back attempt.
First of all, we split off the UI side of the project to focus solely on the API. This way, we’re not held up by anything as we move towards implementation inside of core. We can tackle each UI separately and that helps us keep the project nimble and on track.
The goals of this new API proposal will be to be implemented across WordPress objects as an API to register fields and sections for. We aim to cover these objects (not necessarily in this order):
- Customizer (retrofitting it beneath the existing Customizer API)
- User profile screen
- Post editor
- Settings screens (retrofitting it beneath the existing Settings API)
- And other areas in the future (Comment editor, Network Settings screens [see #15691], Media modals, etc)
This API offers a great deal of standardization across all of WordPress and code reusability. It’s paramount for third-party developers, who will be able to utilize these structures in their own plugins and themes, build apps and give access to other developers so they can contextually see what a site really contains. I see the biggest use-case being able to expose the entirety of WordPress to the REST API and giving apps like the WordPress iOS app access to meta boxes and custom fields to display real editor screens with field inputs based on the control types natively.