BingPreview user agent
Operated by Microsoft
BingPreview is the Bing fetcher that generates page snapshots shown in Bing.
The BingPreview bot at a glance
- BingPreview is operated by Microsoft and crawls web pages for a search engine index.
- The robots.txt token for BingPreview is BingPreview.
- Blocking a search engine crawler removes your pages from that search engine's results.
- BingPreview robots.txt support: Yes.
- Recommendation for Generative Engine Optimization (GEO): Allow.
What is BingPreview?
BingPreview has desktop and mobile variants and creates the page snapshots Bing displays.
Bing documents it on the same page as Bingbot.
Should you block BingPreview?
Allow BingPreview unless it causes a measurable load problem.
| Effect on search rankings | Blocking a search engine crawler removes your pages from that search engine's results. |
|---|---|
| Effect on AI visibility | AI features built on that search index, such as Google AI Overviews and AI Mode on top of Googlebot, also lose access to your pages. |
| Follows robots.txt | Yes |
| Recommendation | Allow |
How to block or allow BingPreview
Put the robots.txt rule in the file at the root of every domain and subdomain, for example https://example.com/robots.txt. The token BingPreview is matched case-insensitively.
robots.txt: block
# Block BingPreview
User-agent: BingPreview
Disallow: /robots.txt: allow
# Allow BingPreview
User-agent: BingPreview
Allow: /robots.txt: partial
# Keep BingPreview out of private areas only
User-agent: BingPreview
Disallow: /wp-admin/
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Allow: /Nginx
# Nginx: return 403 to BingPreview
if ($http_user_agent ~* "(BingPreview)") {
return 403;
}Apache
# Apache .htaccess: return 403 to BingPreview
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} (BingPreview) [NC]
RewriteRule .* - [F,L]Cloudflare WAF
# Cloudflare > Security > WAF > Custom rule, action: Block
(http.user_agent contains "BingPreview")How to verify real BingPreview traffic
Microsoft publishes no IP list or reverse DNS pattern for BingPreview, so the user agent cannot be verified. Anyone can send the same string. Rate-limit unusual volume instead of trusting the name.
How to find BingPreview in your server logs
Search the web server access log for the token. The command below counts BingPreview requests per URL on Nginx or Apache.
grep -i "BingPreview" access.log | awk '{print $7}' | sort | uniq -c | sort -rn | head -20For a full report per AI bot, upload the log to the AI Log File Analyzer, a free tool by Justin Hà.
BingPreview FAQ
BingPreview uses the robots.txt token "BingPreview". Microsoft does not publish a full user-agent string, so match the token inside the User-Agent header.
Yes. Microsoft states that BingPreview follows robots.txt rules written for the "BingPreview" token.
Blocking a search engine crawler removes your pages from that search engine's results. AI features built on that search index, such as Google AI Overviews and AI Mode on top of Googlebot, also lose access to your pages.
Add two lines to the robots.txt file at the root of each domain and subdomain: "User-agent: BingPreview" followed by "Disallow: /". The token is case-insensitive. Changes can take up to 24 hours to be picked up.
Not reliably. Microsoft publishes no IP list or reverse DNS pattern for BingPreview, so anyone can send the same user agent. Rate-limit unusual volume instead of trusting the name.
Search your server access log for "BingPreview", for example with: grep -i "BingPreview" access.log. The AI Log File Analyzer by Justin Hà counts visits per AI bot from an uploaded log file.
Sources: Microsoft crawler documentation. Last reviewed by Justin Hà.
See which of these bots actually reach your website
The AI Log File Analyzer by Justin Hà counts visits from GPTBot, ClaudeBot, PerplexityBot and other AI crawlers in your server log, for free. The GEO Technical Package sets up robots.txt, llms.txt and crawler access for AI search.
