Facebook Sharing Debugger: See What Facebook Scrapes
A Facebook sharing debugger shows what Facebook's crawler sees when your link is shared. Enter a URL: we fetch it as facebookexternalhit, check the response and every og: tag Facebook uses, measure the image and render the Facebook card — no login needed.
We request the page with the facebookexternalhit user agent, exactly as Meta's link-preview crawler identifies itself. Free, no signup. Updated Oct 24, 2026 by the AEOeye team.
What does Facebook's crawler see?
Facebook builds previews with a crawler called facebookexternalhit. Meta's documentation says it fetches pages shared in its apps to gather the title, description and thumbnail — and that it may bypass robots.txt for security or integrity checks.
This debugger sends a request with that user agent and shows the status code, redirects, every og: tag and the card Facebook would build from them.
Facebook Debugger Tool: Why Your Old Image Still Shows
Facebook caches. Meta says it caches images by URL, so replacing the file but keeping the same URL can leave the old picture in place. Two fixes:
- Give the new image a new filename or a version query (
card.png?v=2). - Ask Facebook to refresh: paste the page into Meta's official Sharing Debugger and choose "Scrape Again".
Our tool shows what Facebook will see on its next scrape; Meta's tool is the one that clears Facebook's cache.
Facebook Debug Tool Checklist: The og: Tags Facebook Needs
Four tags make a reliable Facebook card: og:title, og:description, og:image and og:url. Add og:image:width and og:image:height so the image renders on the first share. Meta recommends images of at least 1200×630, under 8 MB.
Why does Facebook show no preview at all?
Usually the crawler can't get the page. Firewalls and bot protection often challenge facebookexternalhit, and a page that returns 403 or a challenge gives Facebook nothing to work with.
We saw how common that wall is when we fetched 391 well-known homepages with a labelled research crawler in October 2026 (dataset): 55 answered with a 403. If your firewall blocks unknown crawlers, allow Meta's crawler explicitly.
Compare the Facebook card with five other platforms in the link preview tool, or check the image alone with the OG image checker.
One page checked. What about the rest of your site?
The free SEO audit crawls your site and scores ~90 checks across 7 areas — with the evidence and the fix for each problem.
FAQ
How do I clear Facebook's cache for my link?
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Paste the URL into Meta's Sharing Debugger at developers.facebook.com/tools/debug and click "Scrape Again". If the image still doesn't change, give the image file a new URL.
Do I need to log in to use this debugger?
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No. We fetch your page as Facebook's crawler and show the result without any account. Only clearing Facebook's own cache requires Meta's tool and a login.
Does facebookexternalhit obey robots.txt?
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Meta says it may bypass robots.txt when performing security or integrity checks. To stop previews entirely, you would need to block it at the server or firewall.
Sources
Related free tools
Open Graph Checker
Free Open Graph checker: validate og:title, og:description, og:image, og:url and og:type on any URL, catch broken tags and see the fix for each.
OG Image Checker
What OG image size works? 1200×630 px. Check your og:image dimensions, file size, format and crop on Facebook, LinkedIn, X and Slack in one click.
Link Preview
Free link preview tool: see how a URL looks on Facebook, LinkedIn, X, Slack, Discord and iMessage — from the tags each platform actually reads.
Twitter Card Validator
X retired its Card Validator. Paste a URL to preview your X card, see which tags X reads (twitter: vs og: fallbacks) and fix image errors.