fbclid?A unique token Facebook appends to every link you click on its platforms, so the site you land on can report your visit back to Meta and tie it to your Facebook identity.
Facebook started appending fbclid (Facebook Click Identifier) to outbound links in late 2018, right as browsers began blocking third-party cookies. Every click gets a fresh, globally unique value.
On arrival, the destination site's Meta Pixel reads the token and stores it in a first-party cookie called _fbc. From then on, purchases and page views on that site can be reported back to Meta, through the pixel or through Meta's server-side Conversions API, keyed to the exact click, which Meta can connect to the logged-in account that made it. It is the machinery that makes an ad you scrolled past on Tuesday know you bought the thing on Friday.
Because the token rides along in the URL, it also ends up everywhere the URL goes: your history, your bookmarks, server logs, and any chat where you paste the link, where it keeps pointing back at the click you made.
Yes, unconditionally. The page renders identically without it; the only party that loses anything is Meta's attribution pipeline. Facebook itself still works normally when links you share have it removed.
Rather's Link Shortener strips fbclid and hundreds of parameters like it, right in the address bar and in everything you copy or share. Free, open source, no account, no data collection, and the page you are on never breaks: the cleanup happens after the site has already loaded.