iMessage link previews: how Apple's Messages app uses Open Graph tags
iMessage previews are low-effort to support. Standard og: tags work. The image will be small, so keep it clean and bold. Test by pasting your URL in a Messages conversation with yourself.
Apple's Messages app (iMessage) generates rich link previews using og:title, og:description, and og:image, similar to other messaging platforms. The preview shows an inline bubble with the image at the top, title in bold, and domain name below. iMessage fetches the preview when the sender pastes the URL, not when the recipient views it.
By TechCompare · Updated
How this is calculated
iMessage previews are smaller than other platforms: the image renders at roughly 220x115 in the message bubble. A 1200x630 image will be downscaled significantly, so don't put small text in your OG image and expect it to be readable in iMessage. Apple's LinkPresentation framework (which powers iMessage previews) also respects the website's favicon and displays it as a small icon in the corner of the preview bubble. There's no public debugger or cache-busting mechanism. The preview is generated when the sender pastes, and if it fails (slow server, missing tags), iMessage shows a plain text URL with no preview.
Verdict
Apple's LinkPresentation framework reads og:title, og:description, and og:image and renders them in a bubble roughly 220x115, so fine-text OG images become unreadable. The favicon gets pulled in as a corner icon too. No public debugger means no cache-busting shortcut, and a slow server or missing tags drops the whole preview to plain text. Generate the preview when the sender pastes, not when the recipient opens.