About OG Prism

What it does

Paste a page’s HTML and the social card preview lays out approximate link cards for nine places people share links, with a list of problems to fix. The other tools write the tags (tag generator), make the image (image generator), check its size and crops (size checker), validate X cards (Twitter card validator), list everything in a page’s head (meta tag extractor) and make favicons (favicon generator).

How it works

Everything runs in your browser. The HTML parser, the previews, the canvas image tools and the ICO and ZIP writers are all JavaScript delivered with the page; there is no server-side code and nothing you paste or drop is uploaded. Image addresses that appear in your HTML are loaded by your browser, straight from wherever they are hosted, so the previews can show and measure them. After the first visit the tools keep working offline for as long as the page stays open.

What the previews are, and are not

The previews are approximations built from each platform’s publicly visible behaviour: which tags it reads, how it falls back, how it crops and truncates. They are not screenshots and not produced by the platforms, and they use generic styling rather than any platform’s branding. Platforms change their layouts and caching often, so check a real share before an important launch.

Who runs it

OG Prism is an independent site with no accounts, no advertising and no tracking cookies. It counts page views with Cloudflare Web Analytics, which is cookie-free; the privacy page has the details.