Meta Tag & Open Graph Checker
Read every tag in the head in source order, catch the duplicates that quietly override each other, measure what the share image really is, and see a separate link preview for each platform with the tags it actually reads.
The URL is sent to the DevDome server in a POST body, never in a query string, and the server requests the page and its share image. Your browser never contacts the checked page or its image host. Results are not stored or sent to analytics.
What this meta tag checker tests
The checker fetches your page like a crawler, follows redirects to the final URL, and reads the whole head in source order: the title, the meta description, every rel=canonical, the robots directives (including the X-Robots-Tag header, which is invisible in the page source), every Open Graph property and every X card tag. Duplicates are kept rather than collapsed, because a second og:title or a second canonical is usually the exact bug you came to find, and the first one silently wins.
The declared share image is then fetched with a bounded ranged request, and its format, pixel size and byte size are read from the file itself. A tag that claims 1200 by 630 while the file is 400 by 400 is a real and common problem, and it is invisible to any tool that only trusts the tags. If the image host refuses a HEAD request, a GET is used instead, so a working image is not reported as broken.
Every result is a named check with one of four states: passed, warning, failed, or not tested. Anything the checker could not establish says so. There is no single grade hiding which checks ran, and the rubric is versioned (2026-07-26) so a result you saved last month can be compared with one from today.
Six platforms, six different cards
A single "social preview" is a comfortable lie: the platforms read different tags, fall back differently, crop differently and cache differently. This is the rule set the previews above are built from.
| Platform | Tags it reads, in order | Shape and crop | Cache and refresh |
|---|---|---|---|
og:title → titleog:image | Wide 1.91:1 card when the image is large enough, otherwise a small square thumbnail beside the text. | Facebook caches the scrape. Use the Sharing Debugger and press Scrape Again after fixing tags. | |
og:title → titleog:image | Wide card, close to 1.91:1. LinkedIn hides the description on some feed layouts. | LinkedIn caches a scrape for about a week. Post Inspector forces a re-read. | |
| X (Twitter) | twitter:title → og:title → titletwitter:image → og:image | summary_large_image draws a wide 2:1 image with the title below it. summary draws a small square thumbnail beside the text. | X re-scrapes on its own, usually within a few days. Its public Card Validator was retired in 2022, so there is no button to force it. |
og:title → titleog:image | Small square thumbnail beside two lines of text. The wide image is centre-cropped to a square, so anything near the left and right edges is cut. | WhatsApp caches per link for a long time and gives no way to clear it. Adding a query parameter is the usual workaround. | |
| Slack | og:title → twitter:title → titleog:image → twitter:image | A coloured-bar unfurl: site name, title, description and the image below or beside it. | Slack caches an unfurl for about 30 minutes; re-posting the link after that re-reads it. |
| Discord | og:title → titleog:image | An embed with a left colour bar. The image is a small thumbnail unless twitter:card is summary_large_image, which makes Discord draw it full width. | Discord caches embeds for several minutes to hours; there is no manual purge. |
Recommended image sizes differ too: Facebook: 1200 x 630 (1.91:1). Facebook needs at least 200 x 200 to use an image at all. LinkedIn: 1200 x 627. Smaller images fall back to a square thumbnail. X (Twitter): summary_large_image: at least 300 x 157, ideally 1200 x 628. summary: at least 144 x 144, square. WhatsApp: Square-safe content in the middle. Keep the file small: large images are commonly reported to drop the thumbnail entirely. Slack: 1200 x 630 works. Slack scales the image down rather than cropping it hard. Discord: 1200 x 630 for the large form.
Why your browser never touches the checked page
A link preview tool that renders the remote og:image directly in your browser tells that image host who you are: your IP address, your user agent, and the fact that you were investigating that page. Worse, DNS can change between the moment our server validated the hostname and the moment your browser resolves it, so a name that looked like a public CDN to us can point at something on your own network by the time you load it.
So the image is fetched by the DevDome server through the same guarded path as the page, re-validated on every redirect hop, capped in size, checked for a real image signature, and re-served from our domain with the type sniffed from the bytes rather than the type the host claimed. SVG is never re-served. If you want the original, use the explicit link on the image card, which is labelled with exactly what it does.
Meta tags FAQ
What are Open Graph tags?
Open Graph tags are meta tags (og:title, og:description, og:image, og:url) that control how a link looks when shared on Facebook, LinkedIn, WhatsApp, Slack, Discord and most other apps. Without them, platforms guess, and shared links often render as bare text with no image.
Why does my link show no image when shared?
Four common causes, and this checker separates them: the og:image tag is missing; the image URL returns an error or is blocked for external requests; the file is not really an image, or is too large or too small for the platform to accept; or the platform cached an old version of your page. The first three are measured here from the bytes the server actually received. The fourth needs a re-scrape with the platform debugger, linked next to each preview.
Does this tool load the checked page’s image in my browser?
No, and that is deliberate. Loading a stranger’s image URL directly would hand that host your IP address and request headers, and a hostname that resolves to a public address for our server can resolve to a private one for you. The DevDome server fetches the image, checks it, and re-serves the bytes from our own domain with the type it sniffed from the file. If you want to open the original, there is an explicit link that says so.
What size should an og:image be?
Use 1200 by 630 pixels. That ratio (1.91:1) renders as a full-width card on Facebook, LinkedIn and X with summary_large_image, and stays sharp on high-density screens. Facebook ignores images smaller than 200 by 200 entirely, and X and LinkedIn reject files above 5 MB. The checker reports the real pixel size and byte size read from the file, not the size your tags claim.
Do I need separate Twitter Card tags?
Mostly no. X falls back to Open Graph tags for the title, description and image. The one tag with no Open Graph equivalent is twitter:card: it selects the layout, so set it to summary_large_image unless you want the small square thumbnail. X retired its public Card Validator in 2022, so there is no button that forces a re-scrape any more.
Why does the same page look different on WhatsApp and Facebook?
Because they are different renderers with different rules. Facebook and LinkedIn draw a wide 1.91:1 card, WhatsApp centre-crops to a small square, X follows twitter:card, Slack draws a coloured-bar unfurl, and Discord only goes full width when twitter:card is summary_large_image. Each preview here is labelled with the tags that platform actually reads and the fallback order it uses, instead of showing one card and calling it all six.
Can I check a page before it is published?
Yes. Switch to Paste HTML, paste the head of your page, and the analysis runs entirely in your browser: nothing is uploaded and no request is made. That is also how you check a staging or localhost page our server cannot reach. The trade-off is that nothing can be fetched, so the image checks and the HTTP-level checks report "not tested" rather than guessing.
Do meta tags affect Google rankings?
The title tag matters directly. The meta description does not affect ranking but controls your snippet and click-through rate. Open Graph tags do not influence rankings at all, but they decide whether social shares of your content look clickable or broken, which drives the traffic that earns links.
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