Create custom field type with dynamic data I would like to create a custom dropdown field with dynamic data

Ideally I would get data from one of my services, and then inject it dynamically in the HTML select field

I read the plugin documentation on custom field types, but couldn't find anything about this
You should have a look at the LJ Dynamic Fields plugin, it sounds like everything you’re after is already doable with this plugin and if not, you can study the code or build upon it.