The Facebook Insights API allows you to get Insights information on your Facebook Page as well as its posts.
Note that Facebook’s method to create a non-expiring page access token is subject to change without notice by Facebook.
To Create A Non-Expiring Page Access Token
To use the Facebook Insights API, you should use a non-expiring Page Access Token. For instructions on how to get such a token, check out this blog post for more details.
The available metrics for the Page Insights can be found in Facebook’s developer documentation.
To determine the page slug
If your Facebook page is https://facebook.com/mycoolfacebookpage, then mycoolfacebookpage is your slug. If your page doesn’t have a name and uses a number instead, then enter that number in this field.