What is MicrosoftPreview?
It generates page snapshots for Microsoft products.
Fetches a page when someone shares its link, to draw the preview card. Blocking it breaks your previews in that app.
Microsoft names no separate robots.txt token for MicrosoftPreview.
MicrosoftPreview user agent
Microsoft documents these user agents for MicrosoftPreview. Version numbers in it change over time, so match on the name, not the whole string.
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; MicrosoftPreview/2.0; +https://aka.ms/MicrosoftPreview) Chrome/W.X.Y.Z Safari/537.36
Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/W.X.Y.Z Mobile Safari/537.36 (compatible; MicrosoftPreview/2.0; +https://aka.ms/MicrosoftPreview)Should you block MicrosoftPreview?
Allow it. Blocking it breaks the preview card when someone shares your link.
How to block MicrosoftPreview in robots.txt
Microsoft documents no robots.txt token for MicrosoftPreview that we could confirm, so we don’t suggest one here. Block it at your server or firewall by user agent instead.
How to verify a request is really MicrosoftPreview
Anyone can send any user agent, so the string alone proves nothing.
Or check by reverse DNS: look up the hostname of the request’s IP, confirm it ends in search.msn.com, then look that hostname up again and confirm it points back to the same IP.
See when MicrosoftPreview reads your site
Bots don’t run JavaScript analytics, so a script tag never sees them. invisit records crawler reads on the server instead, through its server SDK or a Cloudflare Worker, and shows which bots read which pages, next to your visitors.
Checked against Microsoft’s own documentation on . Something changed? Write to help@invisit.dev.