Help Centre

Slack uses Open Graph tags to build link previews. If no image appears, one of these is likely the cause:

• Missing og:image tag — the page's HTML contains no <meta property="og:image">. Paste your URL into Previewcard to confirm — it will show "missing" in red for any tag Slack expects.
• Relative image path — if og:image is set to something like /images/share.png instead of https://example.com/images/share.png, Slack cannot resolve it. Previewcard flags this.
• Image too small — Slack prefers images at least 200×200 pixels. Smaller images are ignored. Previewcard reports the image dimensions it finds.
• Image URL returns a 404 — even a correctly absolute URL is useless if the image server returns a 404. Previewcard fetches the image URL and reports its HTTP status.

Paste the URL into Previewcard, check the image detail section, and fix whatever it flags.

LinkedIn is the strictest platform for Open Graph images. The most common issues:

• Wrong dimensions. LinkedIn's recommended og:image size is 1200×630 pixels (1.91:1 aspect ratio). Images that are too small or the wrong shape may be cropped or not displayed. Previewcard shows you the exact dimensions.
• LinkedIn caches aggressively. Even after you fix the tags, LinkedIn may show the old preview for days. Use LinkedIn's Post Inspector to force a refresh. Previewcard fetches your page fresh every time, so it always shows the current state.
• Fallback behaviour. LinkedIn reads og:title and og:description — it does not fall back to twitter: tags if those are missing. If your page only has Twitter Card tags, LinkedIn will show a bare URL. Previewcard shows you what each platform will render.

A link that looks "broken" in a social feed usually has one or more of these problems:

• No og:title — platforms need a title to render a card. Without it, many platforms show just the bare URL.
• No og:description — a missing description leaves the card looking empty below the title.
• Missing or broken og:image — without an image, the card is text-only, which looks like an error or an old-style link.
• Platform-specific gaps — LinkedIn reads og: tags, Twitter reads twitter: tags (with fallback to og:), and Slack reads og:. A page with only twitter:title works on Twitter but looks broken everywhere else.

Run the URL through Previewcard. It will tell you exactly which tags are missing for each platform and whether the image resolves.

Yes — that's exactly what Previewcard is built for. Paste the URL of the page you're about to publish (or a staging/draft URL that's publicly accessible) and Previewcard will show you how it will look on LinkedIn, Twitter, Slack, and Facebook.

One important note: Previewcard fetches the page as it exists right now. If your page is behind a login, a staging wall, or a VPN, the check will fail — the page needs to be publicly accessible for Previewcard (and social platforms) to reach it.

No. Previewcard is designed to be stateless:

• URLs you submit are processed and the result is returned to your browser. No copy of the URL, the page content, or the result is stored server-side.
• There are no accounts, no logins, and no user profiles.
• The site sets no cookies, no tracking pixels, and uses no analytics scripts.
• Every check is a fresh, independent request.

See the Privacy Policy for the full details.

Currently, Previewcard's rate limit is generous enough for individual use — checking your own links before publishing. There is no hard limit published because the service is free and stateless.

If you need to check a large number of URLs programmatically, the planned Pro plan will include a higher rate limit (500 checks/hour) and API access. These are not yet available. See the Pricing page for the current state of planned features.

This means Previewcard could not fetch the page at all. Common causes:

• The URL is invalid or mistyped.
• The page is behind a login, paywall, or IP restriction.
• The server took too long to respond (timeout).
• The domain does not resolve (DNS failure).
• The URL returns a non-HTTP response (e.g., it points to a file download).

When the check does not complete, it is not a finding about your page's tags — it simply means Previewcard could not reach the page to read them. Check that the URL is correct and publicly accessible, then try again.