When someone pastes a URL into a Notion page and creates a bookmark block, Notion’s server-side crawler fetches the page and extracts Open Graph meta tags to build a rich preview card. The crawler identifies itself with a user agent containing “Notion” and does not execute JavaScript.
This guide covers how Notion’s crawler works, which tags it reads, image handling, cache behavior, and the most common issues with bookmark previews – including the important distinction between bookmark blocks and Link Preview integrations.