Existing endpoints in OpenStack
OpenStack knows three types of endpoints:
Public Endpoints
Internal Endpoints
Admin Endpoints
Each of these endpoint types is designed for a specific purpose. Public endpoints are meant to be used by the OpenStack users to work with OpenStack. Internal endpoints are meant to be used by the OpenStack services to communicate with each other. Admin endpoints are meant to be used by OpenStack administrators.
Out of those three endpoint types, only the admin endpoint sometimes contains APIs which are not available on any other endpoint type.
To learn more about OpenStack endpoints please visit the official OpenStack documentation.