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Link Preview Tester

Test how a URL unfurls on LinkedIn, X, Facebook, and Slack in one check, with the Open Graph tags validated behind it.

Try a live site:

Enter a URL and the cards LinkedIn, X, Facebook, and Slack would build for it appear here, with a check of the tags behind them.

One URL, four different cards

Every platform builds its link card from the same source: the Open Graph tags on your page. But each one draws a different card from them, and each ignores different tags.

That is why a link can look sharp in Slack and broken on LinkedIn. Testing one platform tells you about one platform; the grid above shows all four at once.

PlatformWhat its card shows
LinkedInImage, title, domain. Ignores the description.
XImage with the title overlaid. Wants twitter:card set to summary_large_image.
FacebookImage, domain, title, and one line of description.
SlackSite name, linked title, description, then the image.

The tags that drive every preview

  • og:title is the card title everywhere. Without it, platforms fall back to the page <title>.
  • og:image is the card image everywhere. 1200×630 pixels at a 1.91:1 ratio satisfies all four platforms.
  • og:description shows on Facebook and Slack. LinkedIn reads it but no longer displays it.
  • twitter:card set to summary_large_image gives X the full-width image instead of a small thumbnail.
  • og:url names the canonical address, so shares of variant URLs consolidate on one card.

When a preview is wrong or missing

  1. Run the URL through the tester above and fix whatever fails.
  2. Confirm the page is public. Login walls and firewalls stop every platform's crawler.
  3. Refresh the platform's cache: LinkedIn re-crawls via its Post Inspector, and Facebook via its Sharing Debugger. X and Slack refresh on their own schedule.
  4. Test again here, then share a draft to confirm on the platform itself.

How platform crawlers read your page

The first time a URL is shared, the platform's crawler fetches the page once, reads the meta tags in the head, and builds the card from what it finds. It does not run your JavaScript the way a browser does, so tags injected late by a script are often invisible to it.

Crawlers also announce themselves with their own user agents. Firewalls, bot protection, and geo-blocks that treat them as bots get an empty card as a reward. If your tags look right but no platform sees them, what the crawler receives is the thing to check, and that is exactly the fetch this tester performs.

Debugging by symptom

SymptomMost likely cause
No image on any platformog:image missing, relative, or pointing at a blocked URL
Image shows on X onlytwitter:image is set but og:image is not
An old title or image keeps showingThe platform's cache; refresh it after fixing the tags
Card is fine here, broken when sharedThe page serves crawlers different HTML, often a bot rule
Text-only cardImage too small, wrong format, or served over plain http
Wrong page title entirelyNo og:title, so the platform fell back to a weak <title> tag

Terms on this page

TermWhat it means
Open GraphThe meta-tag standard (og:title, og:image…) every major platform reads.
UnfurlSlack's word for expanding a pasted link into a preview card.
twitter:cardThe extra tag X reads to pick a small or full-width card.
CrawlerThe platform's bot that fetches your page once to build the card.
Canonical URLThe single address shares consolidate on, set by og:url.

Frequently asked questions

How do I test a link preview before sharing it?
Paste the URL into the tester above. It fetches the page the way a platform crawler does, reads the Open Graph and Twitter tags, and renders the card LinkedIn, X, Facebook, and Slack would each build. The checklist under the cards names any missing or weak tags and how to fix them.
Why does my link preview look different on each platform?
Each platform draws its own card from the same tags. LinkedIn shows image, title, and domain but drops the description. Facebook and Slack show the description. X wants an extra tag, twitter:card, to decide between a small thumbnail and a full-width image. One page can pass on three platforms and look broken on the fourth.
What size should a link preview image be?
1200×630 pixels, a ratio of roughly 1.91:1, works everywhere. LinkedIn documents 1200×627 and the others accept the same shape. Keep it under 5 MB as a JPG or PNG, serve it over https with an absolute URL, and avoid images narrower than about 200 pixels, which tend to get dropped.
How do I refresh a cached link preview?
Fix the tags first, then force a re-crawl where the platform allows it. LinkedIn re-crawls when you inspect the URL in its Post Inspector. Facebook re-crawls from its Sharing Debugger. X and Slack do not offer a public refresh button; their caches expire on their own within hours to days.
Is this the same as the LinkedIn link preview checker?
Same engine, wider lens. The LinkedIn checker goes deep on one platform, including its image rules and cache behaviour. This tester shows all four cards side by side, which is the faster way to catch a tag that only one platform depends on.
Do you store the URLs I check?
No. The server fetches the page once to read its tags, returns the result to your browser, and keeps nothing. Checks are rate limited per visitor to keep the tool fast for everyone.
What is Open Graph?
A small meta-tag vocabulary, og:title, og:description, og:image, og:url and friends, that a page uses to describe itself to other platforms. Facebook introduced it, and it became the shared standard: LinkedIn, X, Slack, and most chat apps all read it when building a link card.
Do I need different tags for each platform?
Mostly no. One good set of Open Graph tags covers LinkedIn, Facebook, and Slack. The one platform-specific tag worth adding is twitter:card set to summary_large_image, which tells X to use the full-width image instead of a small thumbnail.
Will fixing these tags fix WhatsApp and iMessage too?
Usually yes. Most chat apps build their link previews from the same Open Graph tags this tester validates, so a page that passes here tends to unfurl properly there as well. Each app has its own cache, so an old preview can linger after the fix.
How long do platforms cache a link preview?
Each platform keeps its own cache and publishes no promise. LinkedIn's is commonly around a week unless you force a re-crawl with Post Inspector. Facebook holds a preview until the Sharing Debugger re-scrapes it. X and Slack expire theirs on their own, typically within hours to days.
Can I test a staging or localhost page?
Only if it is reachable from the public internet, because the check is a real server-side fetch, the same as a platform crawler would make. Localhost and private staging hosts are not reachable. A temporary tunnel to the staging page works; password-protected pages will not.

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