A Facebook id (AKA Fid) is a unique numeric identifier that every Facebook user/page/group/event has.
Sometimes, the user ID will be displayed on the user profile’s URL, after “id=”. For example – https://www.facebook.com/profile.php?id=100002123123123
If not, on the user’s profile, right-click on any empty space, and choose – ‘View page source’ (or just ctrl+ u) – it will open the HTML file of the page.
Use ctrl+F to search for the term – ‘entity_id‘. the following number is the user’s Facebook ID.
In the new Facebook interface, instead of ‘entity_id‘ search for:
- User Profile- ‘userid‘
- Page – ‘pageid‘
- Group – ‘groupid‘
- Event – ‘eventid‘