Open Graph checker

Check a page's Open Graph and Twitter card tags, see the link preview on X, LinkedIn and Slack, and get a list of fixes: image size and shape, missing tags, lengths. Free.

Free · No sign-up

How to use it

01

Enter a public URL

Your launch post, docs page or release notes.

02

We fetch it like a crawler

We read the og: and twitter: tags, then download the image to check its size and shape.

03

Fix what's flagged

Previews for X, LinkedIn and Slack, and a list of fixes, most serious first.

The tags every shared page needs

Platforms build link previews from a handful of tags in the page's <head>:

  • og:title and og:description: the headline and summary. Keep titles under about 70 characters.
  • og:image: an absolute https URL to a PNG or JPEG, ideally 1200×630.
  • og:url or a canonical link, so shares with tracking parameters count as one page.
  • twitter:card set to summary_large_image for the large card on X.

Image size and shape

Large cards on X and LinkedIn are about 1.91:1, so 1200×630 is the safe size. Smaller images fall back to small cards, and other shapes get cropped. SVG images don't render as previews on these platforms; X rejects card images of 5 MB or more; and add og:image:alt so screen reader users know what the image shows.

Fixed it, but the old preview still shows?

Platforms cache previews. LinkedIn's Post Inspector refreshes its cache when you inspect the URL again, and X refreshes its card cache after some time. Adding a query string (?v=2) makes a fresh URL in the meantime.

DevRelay does this for every release. DevRelay drafts launch posts for every release, and renders an on-brand launch image that attaches to the post once you approve it. Start free.
FAQ

Questions about this tool.

01Why can't it read my page?

It fetches pages the way a crawler does, without JavaScript. If your tags are added by client-side JavaScript, crawlers can't see them either: render them on the server.

02Can it check pages behind a login or on localhost?

No. It only fetches public http(s) pages, and never private or internal addresses.

03Do the previews match exactly?

They're close approximations of each platform's card. Each platform changes its layout from time to time.

04Is anything stored?

No. The page and image are fetched, checked and discarded.

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DevRelay drafts launch posts for every release, and renders an on-brand launch image that attaches to the post once you approve it.

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No credit card · Nothing posts without your approval