Open Graph and link preview checker
Enter a URL and see the card that gets drawn when somebody shares it, beside every tag we found and everything that is wrong with them.
Our server fetches the page you name. The preview image is loaded by your browser straight from the site being checked, so no picture passes through us.
What a link preview is built from
A link preview is built from meta tags in the head of the page. Facebook wrote the Open Graph protocol and everything else adopted it, so og:title, og:description, og:image and og:url do most of the work. X reads the same tags and adds its own: twitter:card decides whether the picture runs full width or sits as a thumbnail, and twitter:title, twitter:description and twitter:image override the Open Graph ones when they are set. Anything a page leaves out falls back, first to the other namespace and then to the title element and the meta description, which is why a page with no tags at all still gets a card.
Why a preview still looks wrong after you fixed it
Platforms cache what they read. Facebook, LinkedIn and X each keep their own copy of a page they have already scraped, often for days, so a card that was wrong when it was first shared stays wrong long after the tags were fixed. Each of them has a debugger that refetches on demand, and that is the only way to clear one. This page never caches, so if the tags read correctly here and the card is still wrong out there, it is a cached copy rather than your markup.
Questions about link previews
See the page as the person reporting it saw it
Session Replay captures the page, the console and the network calls beside the bug report, so the next person to look at a broken share already has the whole thing in front of them.