When a link is pasted into a social app, the app fetches the page and reads a handful of meta tags from its HTML. Get these right and every share becomes a clean card with a headline and picture.
Open Graph and Twitter tags used for link previews
| Tag | What it controls | Recommendation |
|---|
og:title | Headline of the card | Up to about 60 characters |
|---|
og:description | Line of text under the headline | One or two sentences, up to about 150 characters |
|---|
og:image | The picture | Absolute https URL, 1200×630 px, under 1 MB |
|---|
og:url | Which URL shares are counted against | The page’s canonical URL |
|---|
twitter:card | Card layout on X | summary_large_image for a big image |
|---|
Frequently asked questions
Why does my link show no image when shared?
The page is missing an og:image tag, the image URL is relative instead of absolute, the image returns an error, or the file is too large or blocked for bots. The checker loads your og:image and tells you which of these it is.
What size should an Open Graph image be?
Use 1200×630 pixels (a 1.91:1 ratio) in JPEG or PNG, ideally under 1 MB. Facebook, LinkedIn, X and Slack all display that size well. Smaller images are shown as a small thumbnail, and other ratios get cropped differently by each app.
I fixed my tags but the old preview still shows. Why?
Social apps cache previews for days. Paste the URL into the Facebook Sharing Debugger or LinkedIn Post Inspector and ask them to scrape it again. On WhatsApp and Slack, a new URL (for example with ?v=2) shows the fresh preview.
Which tags control link previews?
og:title, og:description, og:image and og:url control previews on Facebook, LinkedIn, WhatsApp, Slack, Discord and iMessage. X also reads twitter:card (use summary_large_image for a big image) and falls back to the Open Graph tags.
Is the link preview checker free?
Yes. It is free with no signup, and you can export the result as PDF, CSV or JSON, or copy a fix prompt for Claude Code, Codex or Cursor. It is built and run by Mecverse.
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