Link preview checker
Paste a link to see the card it gets when you share it, and what's missing from its tags.
Big card (most social sites)
On each app
Apps don't all read the same tags, so the same link can look different on each one.
Facebook reads og: tags only. An image narrower than about 600 px shows as a small square instead of across the top. After you fix a page, its Sharing Debugger fetches it again.
X reads twitter: tags first, then og: tags. It gives the big card only with twitter:card set to summary_large_image, and the big card shows just the image and the domain, no title.
LinkedIn reads og: tags only, never twitter: ones, and shows no description. Small images get a thumbnail. Its Post Inspector fetches a changed page again.
Telegram reads og: tags, then twitter: ones. It puts the site name on top, and a big image only when the picture is wide enough; otherwise a small one in the corner.
WhatsApp reads og: tags only. The image should be at least about 300 px wide and under about 600 KB, or it shows a small square or nothing.
Google results don't use og: tags. They show the <title> and meta description, cut at about 60 and 155 characters, and Google may rewrite them.