I want to re-use the frontend tag/category selector that is used when editing a post in the WordPress Admin. I have my own data API that I want this to connect to, rather than searching for tags/categories.
Currently it requests a URL and gets a JSON response of categories (or tags). I would point it at my API URL and would send back data. This would then be displayed as options that the user could select.
Any help with this would be appreciated. I've been reading through WordPress core code for a few hours and haven't made any progress yet!