WhatsApp uses standard Open Graph meta tags to generate link previews in chats. It shares crawling infrastructure with Facebook (via facebookexternalhit) and starts fetching URLs as you type, before the message is even sent. Because it doesn’t execute JavaScript, your OG tags must be present in the initial HTML response.
This guide covers how WhatsApp’s crawler works, which tags produce the best previews, image sizing, cache behavior, and the most common issues that prevent previews from appearing.