Open Graph Protocol
A set of `<meta property="og:...">` tags that lets a web page describe how it should appear when shared on social platforms, including title, description, image, and type.
Open Graph is a metadata protocol originally introduced by Facebook in 2010 and now used by virtually every social platform and messaging app to render link previews. A page adds tags like `<meta property="og:title" content="...">`, `og:description`, `og:image`, `og:url`, and `og:type` inside the `<head>`. When a URL is pasted into Facebook, LinkedIn, Slack, Discord, or iMessage, the platform fetches the page, reads the OG tags, and uses them for the unfurled card. Twitter uses its own `twitter:card` tags but falls back to OG when those are missing. The og:image should be at least 1200x630px to render well across platforms.