fb-page-dual-id

A Facebook Page has TWO different identifiers: the URL ID seen in profile.php?id=N (and in the page's vanity URL) and the Graph API ID returned by me/accounts / used in API calls. They are NOT interchangeable. Worse, the New Pages Experience reuses the profile.php?id=N URL shape for Pages too, so the URL no longer tells you whether a target is a Page or a personal Profile. Store and match on the Graph API ID.