Open Graph Preview and Link Preview Checker

When someone pastes a link, the app's server fetches the page and reads the tags in its head: og:title, og:description, og:image, og:url and og:site_name from Open Graph, and on X the twitter: tags first. It builds a card from them and caches it.

Two consequences catch people out:

• Crawlers read the HTML the server sends. Apple's guidance for Messages states that link previews do not run JavaScript or follow meta refresh redirects, though server-side redirects are followed (Apple). Tags added by client-side JavaScript are often invisible to preview crawlers, so render them on the server.
• Previews are cached. After you fix a tag, old shares may keep the old card. Ask the platform to fetch the page again with the Facebook Sharing Debugger or the LinkedIn Post Inspector; other apps refresh on their own schedule.

This tool fetches the page the same way, from a server, without running scripts, so what you see is what a crawler gets.

Check these in order. The checklist in the tool tests most of them for you:

1. No og:image, or a relative one. /og.png must be a full URL such as https://example.com/og.png.
2. The image cannot be fetched. It sits behind a login, hotlink protection or a firewall, or the URL returns an HTML error page instead of an image.
3. The image is too small or the wrong format. Facebook's minimum is 200×200 pixels, and X does not support SVG.
4. The page blocks bots. A login wall, a cookie wall or bot protection shows the crawler a challenge page instead of your tags. If this tool cannot fetch your page, many platforms probably cannot either.
5. The tags are added by JavaScript, so the crawler never sees them.
6. No twitter:card. X may still show a small summary card from Open Graph, but a large image needs summary_large_image.
7. An old cached preview. Re-scrape it with the platform's debugger.

Use 1200×630 pixels, PNG or JPEG, under 5 MB, and keep text and faces away from the edges so a crop does not cut them. That one image satisfies every major platform:

Also declare og:image:width and og:image:height. Facebook says they let its crawler render the image on the very first share instead of downloading and processing it first.

Facebook, LinkedIn, X and Apple document what they read; Slack, Discord and WhatsApp publish less, so their rows describe how their previews usually appear. When og:title or og:description is missing, most apps fall back to the title element and the meta description, which often carry extra branding. Set them explicitly. To write a full set of tags from scratch, use the meta tag generator.

The cards are close approximations, not screenshots. Each platform changes its layout from time to time, crops differently on phones and desktops, and may show its cached copy. Use them to catch problems early, then confirm with the platform's own debugger before a launch.

Privacy depends on the mode:

• Paste HTML runs entirely in your browser. Nothing is uploaded, which makes it the right choice for staging and local pages.
• Fetch a URL sends only the URL to Playxoft's server. It refuses private and internal network addresses, follows at most three redirects, reads no more than the first 512 KB of the page and stops at the end of the head, gives up after 5 seconds, and returns only the parsed tags. Results are cached for 10 minutes; the page itself is never stored.

In both modes, preview images load straight from your site into your browser.