All our add-on applications are exclusive to VitalPBX. So, it is not possible to install VitalPBX add-ons on other Asterisk distributions.
Yes, VitalPBX does have an API available. You can learn everything you can do with our API on our documentation,
https://documenter.getpostman.com/view/5481262/2s935hQmgP
Our API is constantly growing, so new features are added to it periodically.
