Free Social Share Preview

Enter the page's address and run the check. It fetches the page once, as our checker, and reads the tags in its head: the Open Graph tags (og:title, og:description, og:image, og:url), the Twitter card tags (twitter:card, twitter:title, twitter:image and the rest), the page title and the meta description. Then it fetches the share image once, reading only the start of the file, which is enough to tell what kind of image it is and how big it is.

Each app picks its text and image from those tags in its own order. X reads twitter:title first and falls back to og:title, as its docs say; Facebook reads og:title and, by common report, falls back to the page title; Apple's docs say iMessage shows no description for most links. The preview applies each app's order and draws the card it would build, so a page that looks right on one app but wrong on another shows the difference side by side.

• A card for each of the seven apps, with the title, description and image that app would use.
• The share image's status, format, file size and width and height, read from the file itself.
• Problems listed per app: a missing tag, an image below that app's minimum, a file over its size limit, a title longer than it shows.
• How to make each app read the page again after you fix it, with its own tool named and linked where it has one.

Where an app publishes its rules, the preview follows them and links to the page they come from. Where an app publishes nothing, as Discord does for link previews, the card says the behavior is observed, not official. Like most of these apps, the checker reads the HTML the server sends and does not run JavaScript, so tags added by a script after the page loads will be missing here and probably on shared links too.

Meta's own tool is called the Sharing Debugger. Sign in with a Facebook account, paste the page's address and select Debug. It shows the tags Facebook's crawler found, the preview it will build, any warnings, and when the page was last read. Select Scrape Again after you change the tags to make Facebook read the page now instead of waiting for its cache to expire.

The Sharing Debugger caches images by their address, so changing the picture behind the same image URL does not change the preview. Give the new image a new file name. Meta's sharing guide also suggests running a new page through the debugger before you share it, so the image is already cached the first time someone posts the link.

This page is not the Sharing Debugger and does not see what Facebook's crawler sees. It reads the same tags with our own checker, applies Meta's published image rules, and shows the Facebook card next to six other apps, with no sign-in. Use it to find problems, and the Sharing Debugger to make Facebook read the fixed page.

Meta's tool: Sharing Debugger

Post Inspector is LinkedIn's own tool for link previews. Enter a page's address and it reads the page the way LinkedIn does, shows the title, description and image LinkedIn will use, and lists the tags it found. Inspecting a page also refreshes LinkedIn's saved copy, so new posts get the current preview. LinkedIn may ask you to sign in before it runs.

LinkedIn's help lists the tags it needs: og:title, og:description, og:image and og:url. It asks for an image of at least 1200 by 627 pixels, about 1.91 to 1, up to 5 MB, and says that an image which meets those rules but still does not appear may be blocked by the site from LinkedIn's crawler.

The LinkedIn card on this page checks the same tags and LinkedIn's published image size and file limit. It cannot clear LinkedIn's cache: only Post Inspector can.

LinkedIn's tool: Post Inspector

X still has a page called the Card Validator, and it now asks you to sign in. As widely reported, it no longer shows a card preview; pasting the link into a new post shows the card in the composer, below the text, before you post it. X's docs say card content is cached for 7 days after a link is posted.

X's Cards markup reference sets the rules the X card on this page follows. twitter:card picks the layout: summary for a small square image, summary_large_image for a wide one. twitter:title (up to 70 characters), twitter:description (up to 200) and twitter:image each fall back to their Open Graph tag when missing. The large card's image must be at least 300 by 157 pixels and under 5 MB, and X does not support SVG.

The X card here draws the small or large layout from your twitter:card tag and flags a title over 70 characters, an image below X's minimum and an image X will not show.

X's page (it asks you to sign in and, as widely reported, no longer shows a card preview): Card Validator

Open Graph tags tell apps what to show when someone shares a link. The Open Graph protocol, created at Facebook, defines og:title, og:type, og:image and og:url as the basic four, with og:description and og:site_name among the optional ones. Almost every app that builds link previews reads them, which is why one set of tags can serve Facebook, LinkedIn, Slack, WhatsApp, Discord and iMessage at once.

X reads its own twitter: tags first. Its docs say each one falls back to the Open Graph tag with the same job, so twitter:title falls back to og:title and twitter:image to og:image. The one X tag with no Open Graph twin is twitter:card, which picks the small summary card or the large image card. Without it, X's docs say a page with Open Graph tags may get the small card.

Write the tags in the page's HTML, not with a script. Use a full https address for og:image and og:url, keep the site name out of og:title (put it in og:site_name instead), and give every page its own title, description and image, so shares of different pages look different.

An image of 1200 by 630 pixels, about 1.91 to 1, works on every app in this preview. Meta's image guidelines ask for at least 1200 by 630, show images under 600 by 315 as a small image, and do not accept anything under 200 by 200 or over 8 MB. LinkedIn's help asks for at least 1200 by 627 pixels at 1.91 to 1, up to 5 MB. X's large image card takes images of at least 300 by 157 pixels, about 2 to 1, under 5 MB, in JPG, PNG, WebP or GIF, and does not support SVG.

WhatsApp's docs ask for an image under 600 KB, at least 300 pixels wide and no wider than 4 to 1. Apple's note on previews in Messages asks for images at least 900 pixels wide and says images under 150 pixels wide may be ignored or shown as an icon. Slack and Discord publish no image rules, so the preview does not hold them to any.

The preview reads the width and height from the image file's own header, and the file type from its first bytes, so a real PNG served with the wrong content type is still measured. A size it cannot read is reported as unknown, never guessed. A share image that is a JPEG or PNG of 1200 by 630 pixels and under 600 KB meets every published rule here at once.

Apps cache what they read. Once a link has been shared, the app shows its saved copy until it reads the page again, so a fix to your tags does not appear straight away. How long the copy lasts, and whether you can clear it, depends on the app.

• Facebook: Meta's Sharing Debugger reads the page again when you choose Scrape Again. Images are cached by their address, so a new image needs a new image URL.
• LinkedIn: Post Inspector reads the page again and updates the preview for new posts.
• X: its docs say card content is cached for 7 days after a link is posted.
• Slack: its docs say previews are cached across Slack for about 30 minutes.
• WhatsApp, Discord and iMessage publish no way to refresh. Commonly reported: a new message reads the page again, and messages already sent keep their old preview.

A post that is already published usually keeps the card it was posted with. To show the new card, share the link again after the app has read the fixed page.

Each card follows the entry below, checked against the page linked under it on the date shown. Apps change their rules, so we check these pages again at least once a year. An entry marked observed is behavior commonly cited by developers, not a rule the app publishes.

• Facebook: title from og:title or page title; image from og:image. Tag order: observed behavior, commonly cited. Image sizes are from Meta's image guidelines. Meta says that without Open Graph tags its crawler makes its own best guess, so the fallback to the page title and meta description is observed behavior, commonly cited.

  Source · Checked Oct 29, 2026

• LinkedIn: title from og:title or page title; image from og:image. Tag order: observed behavior, commonly cited. LinkedIn's help lists og:title, og:description, og:image and og:url and asks for an image of at least 1200×627 px, 1.91:1, up to 5 MB. What it shows when those tags are missing is observed behavior, commonly cited.

  Source · Checked Oct 29, 2026

• X: title from twitter:title or og:title; image from twitter:image or og:image. Tag order from its own docs. From X's Cards markup reference: each twitter: tag falls back to its Open Graph tag, and the large image card takes JPG, PNG, WebP or GIF of at least 300×157 px, about 2:1, under 5 MB (SVG is not supported). X has since moved its developer docs; the link is an archived copy of X's page.

  Source · Checked Oct 29, 2026

  X summary card rules · Checked Oct 29, 2026

  X 7-day card cache · Checked Oct 29, 2026

• Slack: title from og:title, twitter:title or page title; image from og:image or twitter:image. Tag order: observed behavior, commonly cited. Slack's docs say it reads oEmbed, Twitter Card and Open Graph tags, with no order and no image rules. The order here (oEmbed first, then Open Graph or Twitter tags, then the page title and meta description) is observed behavior, commonly cited. This check does not read oEmbed.

  Source · Checked Oct 29, 2026

• WhatsApp: title from og:title or page title; image from og:image. Tag order: observed behavior, commonly cited. Meta's WhatsApp docs ask for og:title, og:description, og:url and og:image in a head that ends within the first 300 KB of the HTML, and an image under 600 KB, at least 300 px wide, no wider than 4:1. WhatsApp says it may relax these or check other markup but that this should not be relied on, so the fallback to the page title is observed behavior, commonly cited.

  Source · Checked Oct 29, 2026

• Discord: title from og:title, twitter:title or page title; image from og:image or twitter:image. Tag order: observed behavior, commonly cited. Discord publishes no rules for link previews. Everything in this entry, the tag order included, is observed behavior, commonly cited. The source is the Open Graph protocol, the standard Discord's previews are built from.

  Source · Checked Oct 29, 2026

• iMessage: title from og:title or page title; image from og:image. Tag order from its own docs. From Apple's note on rich previews in Messages: a preview shows og:title (the page title when there is none), og:image and an icon, and no description except for social posts. Images should be at least 900 px wide; under 150 px they may be ignored or shown as an icon. The page itself is limited to 1 MB and its images and icons to 10 MB together.

  Source · Checked Oct 29, 2026