The Facebook Sharing Debugger shows exactly what Meta's crawler sees when it fetches your URL. Use it before every major share and after every OG tag change. It is free, requires no app setup, and covers Facebook, Messenger, and WhatsApp previews.
Short answer
Go to developers.facebook.com/tools/debug, paste your URL, click Debug, review the scraped og:title, og:description, and og:image, fix any warnings on your site, then click Scrape Again. Cross-check with OpenGraph Check for a multi-platform preview.
What the Sharing Debugger does
Meta's crawler (facebookexternalhit) fetches your page HTML and extracts Open Graph tags. The debugger runs the same process and displays:
- Parsed OG properties (title, description, image URL)
- A visual link preview mockup
- Warnings and errors from the scrape
- Redirect chain the crawler followed
- Raw response code
It does not change your website. It only reports what Meta would cache for link previews.
When to use it
| Situation | Action |
|---|---|
| Before launching a campaign | Debug URL, confirm image and title |
| After deploying new OG tags | Scrape Again twice |
| Preview shows old image | Scrape Again after versioning image URL |
| WhatsApp shows wrong preview | Same tool - shared Meta cache |
| New page not previewing | Debug to see missing tags or errors |
For cache-specific workflows, see How to Clear Open Graph Cache on Facebook.
Step-by-step walkthrough
1. Open the tool
Navigate to developers.facebook.com/tools/debug. Log in with a Facebook account if prompted. No developer app is required.
2. Enter your URL
Paste the full canonical URL:
https://example.com/blog/my-post
Include https://. Avoid trailing inconsistencies - pick one format (with or without trailing slash) and stick to it in og:url.
3. Click Debug
The tool fetches your page. Wait for the results panel. A slow server may trigger a timeout warning.
4. Read the Link Preview section
Check three fields:
- Title - from
og:title(falls back to<title>if missing) - Description - from
og:description - Image - from
og:image, shown as URL and thumbnail
If any field is wrong, fix the tag on your live page before scraping again.
5. Review warnings
Common warnings and what they mean:
| Warning | Cause | Fix |
|---|---|---|
Missing og:image | No image tag in HTML | Add og:image with absolute HTTPS URL |
| Image could not be downloaded | 403, timeout, or SSL error | Fix image URL access |
| Redirect path | Multiple redirects | Reduce to one hop |
| Parser mismatched metadata | Conflicting tags | Remove duplicate OG tags |
| Previously cached scrape | Old data still stored | Click Scrape Again |
6. Click Scrape Again
After fixing your page, click Scrape Again to overwrite Meta's cache. Click it twice if the image thumbnail still looks stale.
7. Verify on OpenGraph Check
The debugger only shows Meta's view. Paste the same URL into OpenGraph Check to compare LinkedIn, X, and Discord previews side by side.
Understanding the debug output
Response code
- 200 - Page fetched successfully
- 301/302 - Redirect detected (check final URL matches
og:url) - 403/404 - Crawler blocked or page missing
- 5xx - Server error on your side
Fetched URL vs. input URL
If these differ, you have redirects. Meta caches based on the final URL. Set og:url to match.
og:image preview
The thumbnail in the debugger is served from Meta's CDN after download. If the thumbnail is old but the URL is new, the image file at that URL may not have changed. Version the filename.
Common mistakes when using the debugger
Debugging localhost or staging
The debugger cannot reach localhost or VPN-only servers. Test on a public production URL or a staging domain with public access.
Debugging before deploy finishes
CDN or hosting may still serve old HTML. Confirm your deploy is live by checking page source in an incognito window first.
Ignoring JavaScript-only tags
The debugger reads initial HTML only. If og:image appears in DevTools but not in View Source, fix your SSR setup.
Expecting instant updates in existing posts
Scraping updates Meta's cache for future shares. Already-published Facebook posts keep their original preview. See Facebook Preview Not Updating.
Sharing Debugger vs. other tools
| Tool | Platform | Purpose |
|---|---|---|
| Facebook Sharing Debugger | Meta (FB, Messenger, WhatsApp) | Scrape and refresh cache |
| LinkedIn Post Inspector | Inspect and refresh LinkedIn cache | |
| Twitter Card Validator | X (Twitter) | Validate Twitter Card tags |
| OpenGraph Check | All major platforms | Multi-platform preview |
Each platform has its own cache. Passing the Facebook debugger does not update LinkedIn or X.
FAQ
Is the Sharing Debugger free?
Yes. No paid plan or developer app required.
How often can I scrape the same URL?
No published hard limit, but scrape only when tags change. Excessive scraping may be throttled.
Does it work for Instagram post links?
Instagram feed posts use different mechanics. For URL previews in DMs and Stories link stickers, the same OG cache applies.
Can I debug someone else's URL?
Yes. Any public URL can be debugged. You cannot change their tags, only trigger a re-scrape.
Why does the debugger show tags I removed?
Cached scrape from a previous run. Click Scrape Again after confirming tags are gone from live HTML.
Do I need fb:app_id for the debugger to work?
No. fb:app_id is optional for basic link previews.
Bottom line
The Facebook Sharing Debugger is the official way to test and refresh Meta link previews. Paste your URL, read the output, fix warnings on your site, scrape again, and confirm with a multi-platform checker. Run it after every OG change and before every campaign share.
