Open Graph checker

Open Graph is a set of <meta> tags in a page’s <head> that tell other sites what to show when someone shares the link: og:title, og:description, og:image and og:url are the four that matter. Facebook created it; LinkedIn, WhatsApp, Slack, Discord and most chat apps read it too. X reads its own twitter: tags first and falls back to Open Graph.

1200 × 630 pixels (a 1.91 : 1 rectangle), as a PNG or JPEG, ideally under about 600 KB. That shape fills the large card on X, Facebook, LinkedIn and Discord without cropping, and 1200 pixels wide stays sharp on high-resolution screens.

Keep the important part — logo, headline — towards the centre: apps that show a small square thumbnail (WhatsApp, Slack, iMessage in some cases) crop to the middle. X refuses images over 5 MB, Facebook over 8 MB, and SVG is not shown anywhere.

The usual reasons, most common first:

The image URL is relative (/og.png instead of https://…/og.png). The image is too heavy or too small (under 200 × 200 is ignored by Facebook). Bot protection (a Cloudflare challenge, a firewall rule) answers the preview crawler instead of the page. The old preview is cached: platforms remember what they saw the first time a link was shared.

The checker above tests the first three; the answer below covers the cache.

Each platform caches previews. On LinkedIn, paste the URL into the Post Inspector; on Facebook (which also feeds WhatsApp and Messenger), use the Sharing Debugger and press “Scrape again”.

X no longer has a card validator and refreshes on its own schedule. Everywhere, the quickest fix is to share a slightly different URL — yoursite.com/?v=2 — which every platform treats as a new link and fetches fresh.

You need one: twitter:card set to summary_large_image, or X shows the small square card at best. The rest — twitter:title, twitter:description, twitter:image — are optional, because X falls back to the matching og: tags. Add them only if you want X to show something different.

The data is: the page is fetched the way a preview crawler fetches it, and every fallback each platform applies is followed, so the title, text and image are the ones they will pick. The drawings are close approximations — platforms restyle their cards every so often. A site that answers differently by country or blocks some crawlers by name can still show something different to one platform than to us.