About this tool
Social preview checker, explained
When you share a link on X, LinkedIn or Slack, the platform builds a card from the page's meta tags: a title, a description and an image. This checker fetches your page, shows the card on seven platforms, checks the image file itself, and writes corrected tags you can copy.
How to use it
- 1Enter the page address in the bar, like acme.com/blog/post, and click Preview my link.
- 2Read how many of the seven platforms show a full card, then compare the X, LinkedIn, Facebook, Slack, Discord, iMessage and WhatsApp cards. Click a platform name to see it alone.
- 3Go through the Checks: each tag and the image get Pass, Improve, Fix or Info, with the reason.
- 4Correct the title, description, image, alt text, site name, canonical URL or X card under Fix the tags, switch to With my edits to preview the result, then click Copy tags and paste them into your page.
How it works
How the preview is read
The check runs on a server, since a browser page cannot read another site's HTML. It requests the page as plain HTML, the way link preview crawlers do, without running JavaScript. It follows up to three redirects, gives up after 10 seconds and reads up to 1.5 MB. IP addresses, ports and private networks are refused, and each visitor can run 10 checks a minute.
Each platform reads the tags its own way. X prefers twitter:title, twitter:description and twitter:image, then falls back to the Open Graph tags. The others read og:title and og:description. All of them fall back to the page's title tag and meta description, and to twitter:image when og:image is missing. A relative image path is resolved against the page address, and only http or https images are kept. Titles and descriptions are trimmed at each platform's usual length, for example 70 characters for an X title and 65 for WhatsApp.
The server then loads the start of the image file to read its format and dimensions. The checks flag an og:title over 60 characters or an og:description over 160, a missing or relative og:image, an image that does not load, an SVG (no platform shows it), an AVIF (several skip it), a file over 1 MB or over 5 MB when the server reports its size, an image under 1200 × 630 or under 600 × 315, a shape more than 6% away from 1.91:1, and a missing og:image:alt, twitter:card, og:url or og:site_name. A platform counts as showing a full card when it has a title and an image that loads.
Each platform crops, truncates and caches in its own way, so treat the cards as a close preview. Tags found on the page lists every og:, twitter:, article: and fb: tag the page declares.
When to use it
Ways people use it
Before publishing a post
Check that a new article has its own title, description and image before the first share.
Launch day
Run the launch page through the checker before posting it everywhere, when a broken preview would be seen by the most people.
After a redesign or CMS change
New templates sometimes drop the meta tags. Check a few key pages after the change.
Debugging a blank card
When a shared link shows no image, see whether the tag is missing, the file does not load or is in a format platforms skip, or the platform is showing an older cached version.
FAQ
Questions people ask
Why is my link preview not showing an image?
Usually the page has no og:image tag, or the tag points to a URL that is wrong, not public or relative. The file can also be an SVG, which no platform shows, or too heavy. It can be a cached preview from before you added the tag too. Check the page here first, then ask the platform to refresh its copy.
How do I change the image that shows when I share a link?
Set the og:image meta tag in the head of the page to the full URL of the image you want, ideally a PNG or JPEG of 1200 × 630 pixels under 1 MB. Then ask the platforms that already cached the old version to read the page again.
How do I refresh a LinkedIn or Facebook link preview?
LinkedIn's Post Inspector and Facebook's Sharing Debugger fetch the page again and update their stored preview. Other platforms refresh their cached card on their own schedule.
What are Open Graph tags?
Meta tags from the Open Graph protocol, created by Facebook, that describe how a page should look when shared: og:title, og:description, og:image, og:url and a few others. Most social networks and messaging apps read them.
Do I need Twitter Card tags if I have Open Graph tags?
X falls back to the Open Graph title, description and image when its own tags are missing, so og tags alone often work. Adding twitter:card set to summary_large_image tells X to show the large image layout, and without it X may pick the small card.