The Short Answer
Use a general OG checker first. Then use the platform debugger for the app where the preview is wrong.
I use the general checker to catch the boring mistakes: missing tags, relative image URLs, image fetch failures, wrong dimensions, and tags injected too late by JavaScript. Then I use Facebook or LinkedIn's own tool when their cached preview disagrees.
Start with the Tags
Most debugging goes nowhere until these tags are present in the initial HTML response:
<meta property="og:title" content="Page title">
<meta property="og:description" content="Short description">
<meta property="og:image" content="https://example.com/og.png">
<meta property="og:url" content="https://example.com/page">
<meta name="twitter:card" content="summary_large_image">View source, not just DevTools Elements. A crawler may read the HTML before your client app runs. If the tags only appear after hydration, fix that before opening every debugger on the internet.
Which Tool to Use
| Platform | Tool | Use it for |
|---|---|---|
| Facebook / Messenger | Sharing Debugger | Seeing what Facebook scraped and asking it to scrape again. |
| Post Inspector | Refreshing LinkedIn's cached preview for new shares. | |
| X | Card Validator | Checking twitter:card markup and card rendering. |
| Slack | Composer test | Slack crawls common Open Graph and X Card metadata for classic unfurls. |
| Discord / Telegram / WhatsApp / iMessage | Fresh share test | Checking the real app after fixing tags and changing stale image URLs. |
Use Facebook's Sharing Debugger when Facebook or Messenger shows the wrong title, description, or image. Paste the URL, inspect the scraped data, fix the page, then ask it to scrape again.
If Facebook keeps showing the wrong image, check og:url. I see this bug a lot. Every page points og:url at the homepage, so Facebook treats a product page or article like the homepage.
Use LinkedIn Post Inspector for LinkedIn. LinkedIn's help page says an old image can show because the same URL was cached before. It also says the refreshed preview affects new posts with that URL, while existing posts keep their old preview.
That matters. If a live post already has the wrong card, do not assume the debugger will rewrite history. Fix the page, inspect it, then create a fresh post draft.
X
X Cards use twitter: tags, but X can also fall back to Open Graph values for some fields. Add twitter:card explicitly. The usual choice for OG images is summary_large_image.
X's Cards docs say card content can be cached for seven days after a link with card markup is posted. If the card matters now, change the image URL after updating it.
Slack and Chat Apps
Slack's docs say classic unfurling crawls the URL and looks for common Open Graph and X Card metadata. Discord, Telegram, WhatsApp, and iMessage behave like practical black boxes from a site owner's point of view: give them simple server-rendered tags and public image URLs.
For these apps, I do not spend long looking for a cache button. I fix the tags, version the image URL, and test a fresh share.
My Debugging Order
- Paste the URL into MyOG's preview tool.
- View source and confirm tags are in the first HTML response.
- Use the Chrome extension when you want to inspect the current page without switching tools.
- Open the platform debugger for the app that is wrong.
- Fix crawler access: HTTPS, redirects, auth, robots, firewall, content type.
- If the preview is still stale, follow the cache clearing checklist.
Related Resources
- How to Clear Cached OG Images - when the tags are fixed but the preview is stale
- OG Meta Tags Guide - the tags each crawler starts from
- OG Checker Chrome Extension - inspect the page you are already looking at
- Crawler Directory - Facebook, LinkedIn, X, Slack, Discord, Telegram, WhatsApp, and more
Debug the page before debugging the platform
MyOG.social checks the Open Graph tags and renders previews so you can fix the page before fighting a platform cache.
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