Link preview checker.

What a link preview is.

When someone pastes your link into a chat, a feed or a post, the platform fetches the page and reads a few tags from its <head>, mostly Open Graph tags (the og: ones) and X's twitter tags. From those it draws the card: a picture, a title and a line of description. If the tags are missing, the card is a bare address, and bare addresses get fewer clicks than cards.

The tags that matter.

• og:titleThe headline of the preview. Keep it to about 60 characters; many platforms cut it off after that. If it's missing, platforms use the page's <title>.
• og:descriptionOne or two sentences under the headline. 50 to 160 characters is a good range. Put the point first, since long ones get cut.
• og:imageThe picture. Use a full https:// address to an image that loads without a login, 1200 × 630 pixels. Without it, a link shows no picture at all or a random one from the page.
• twitter:cardTells X which card to draw. summary_large_image shows the big picture; without the tag, X may show a small summary card.
• Canonical URLA <link rel="canonical"> says which address is the real one, so copies with tracking parameters don't count as separate pages.

When the preview is missing or wrong.

• You fixed the tags, but the old preview still showsPlatforms remember a link for a while. Facebook and LinkedIn each have a tool for asking them to fetch it again; on most others you wait, or share the link with a harmless extra parameter.
• The tags are in the page, but no preview showsMost preview crawlers don't run JavaScript. Tags that a script adds after the page loads are invisible to them, so they need to be in the HTML the server sends.
• The image address works in your browser but not in the previewImages behind a login, behind hotlink protection, or blocked for automated visitors fail for the crawlers too. Open the address in a private window to test.
• The preview shows the wrong pageCheck og:url and the canonical address. If a site-wide template sets one title and image for every page, each page needs its own.

What this checker can't do.

It asks for your page the way any visitor would, with a crawler that names itself AppAdSwapBot. A site that blocks automated visitors may refuse us even though real previews work. We can tell that your image loads but not how big it is, and the cards we draw are approximations: every platform has its own layout and changes it. For the final word on one platform, use its own debugging tool. See our privacy page for what happens to the address you check.