01 Open Graph & social card preview
Paste a page’s HTML or fill in a few fields. OG Prism reads the Open Graph and Twitter card tags in your browser, lays out approximate previews side by side and lists what to fix.
Resolves relative links when the HTML has no og:url or canonical link.
Simple mode: these fields become og:* tags.
Or upload an image to preview it locally (it stays on your device).
A web page cannot read another site’s HTML, so live pages are checked on WebTraceCheck: its free website audit lists the Open Graph fields, Twitter card tags, favicons and manifest it finds.
Approximate previews: platforms change layouts, crops and truncation often and cache what they fetched, so treat these as a guide, not a guarantee.
Paste the <head> of a page (View Source in any browser shows it), or the whole document. OG Prism reads the same tags the platforms’ crawlers read: og:title, og:description, og:image, og:url, og:site_name, the twitter:* tags, the <title>, the meta description and the theme colour. Each print on the contact sheet applies one platform’s usual fallbacks: X prefers twitter:title over og:title, search results use <title>, and Discord tints its embed with theme-color.
Images are loaded by your browser so the previews can measure them. Small images switch Facebook, WhatsApp and LinkedIn to a thumbnail layout, a summary card gives X a square crop, and a URL that fails to load is flagged. Relative image paths are resolved against <base href>, the page URL you enter, og:url or the canonical link, in that order, and reported, because the Open Graph protocol expects absolute URLs.
No HTML handy? Switch to Edit fields and type the basics, or upload an image to see how it crops before you publish it.
02–07 The rest of the sheet
+ Also useful
Trying a scheduling tool, a social analytics trial or a newsletter platform? Sign up with a free disposable inbox and keep your main address out of their mailing lists. The inbox is instant with no sign-up, there are hundreds of domains to choose from, and messages are deleted automatically after 3 days.
Temp Mail API for automated sign-up tests (opens in a new tab)
Get a temporary inbox (opens in a new tab)Its free website audit reads a live page’s Open Graph fields, Twitter card tags, favicons and web manifest for you. To see the page as a first-time visitor would, open it in a disposable cloud browser: Chrome, Firefox, Edge, Brave or Chromium on an isolated Linux desktop that is deleted after each session.
Website audit (opens in a new tab)Redirect chain checker (opens in a new tab)All free tools (opens in a new tab)
Open the cloud browser (opens in a new tab)The previews are approximations of common layouts. Platforms redesign their cards, crop differently on phones and desktops, and cache what their crawler fetched the first time. After changing tags, ask the platform to fetch the page again (Facebook’s Sharing Debugger and LinkedIn’s Post Inspector have a button for it).
Browsers do not let one website read another website’s HTML, and OG Prism has no server to fetch pages for you. Copy the source of your page and paste it here, or use the Check a live URL box, which opens WebTraceCheck’s website audit for that address.
1200 × 630 pixels (about 1.91:1) is the common recommendation and works as a large card almost everywhere. Below about 600 × 315 many platforms fall back to a small thumbnail. Keep important text near the centre, because X crops to 2:1 and thumbnails crop to a square.
X falls back to og:title, og:description and og:image, so you can skip duplicates. You do need twitter:card, and summary_large_image is the value that gets the big image.
No. Everything is parsed in your browser. The only requests are for images your tags point to, which your browser loads from wherever they are hosted so the previews can show them.