1. hook_init()
It gets called at the beginning of a page request (but after the modules and themes are loaded into memory) and it?s typically used to set global parameters that may be needed in the request. One thing to note about it is that it is not run on cached pages.
2. hook_views_api()
hook_views_api() is not a Drupal core hook but one from the Views module .It is used to register Views API information (including the necessary files for Views) usually for implementing hook_views_default_views().