01 · Operator
Who operates Chrome Privacy Preserving Prefetch Proxy
- Company
- Type
- Other bot
- Official docs
- developer.chrome.com
02 · Behavior
What Chrome Privacy Preserving Prefetch Proxy does
Chrome prefetches likely next pages through a Google proxy, so they load faster after a click. Before prefetching, it checks the site's /.well-known/traffic-advice file. Prefetch requests carry the header Sec-Purpose: Prefetch; anonymous-client-ip and no cookies.
03 · Impact
Why Chrome Privacy Preserving Prefetch Proxy matters for your site
If you allow it
- Pages linked from Google Search can load faster for visitors
- Prefetches do not carry cookies or reveal user IPs
If you block it
- Prefetched pages may never be viewed, adding server load
- Prefetches can inflate server-side page view counts
04 · Allow
How to allow Chrome Privacy Preserving Prefetch Proxy
robots.txt
# Chrome Privacy Preserving Prefetch Proxy has no documented robots.txt token and does not read robots.txt.
# Use a Cloudflare, nginx or Apache rule instead.
Cloudflare
# Security › WAF › Custom rules › Create rule
Expression: (http.user_agent contains "Chrome Privacy Preserving Prefetch Proxy")
Action: Skip › All Super Bot Fight Mode rules
# Also check Security › Bots: "Block AI bots" can block it regardless of robots.txt.
WordPress
# Chrome Privacy Preserving Prefetch Proxy has no documented robots.txt token and does not read robots.txt.
# Use a Cloudflare, nginx or Apache rule instead.
nginx
# nginx serves every user agent by default.
# Make sure no rule like this blocks it:
# if ($http_user_agent ~* "Chrome Privacy Preserving Prefetch Proxy") { return 403; }
Apache
# Apache serves every user agent by default.
# Make sure .htaccess has no rule like this:
# RewriteCond %{HTTP_USER_AGENT} Chrome Privacy Preserving Prefetch Proxy [NC]
# RewriteRule .* - [F,L]
05 · Block
How to block Chrome Privacy Preserving Prefetch Proxy
Start with robots.txt. If Chrome Privacy Preserving Prefetch Proxy keeps showing up in your logs, block it at your CDN or web server.
robots.txt
# Chrome Privacy Preserving Prefetch Proxy has no documented robots.txt token and does not read robots.txt.
# Use a Cloudflare, nginx or Apache rule instead.
Cloudflare
# Security › WAF › Custom rules › Create rule
Expression: (http.user_agent contains "Chrome Privacy Preserving Prefetch Proxy")
Action: Block
WordPress
# Chrome Privacy Preserving Prefetch Proxy has no documented robots.txt token and does not read robots.txt.
# Use a Cloudflare, nginx or Apache rule instead.
nginx
# In your server { } block:
if ($http_user_agent ~* "Chrome Privacy Preserving Prefetch Proxy") {
return 403;
}
Apache
# .htaccess
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Chrome Privacy Preserving Prefetch Proxy [NC]
RewriteRule .* - [F,L]
</IfModule>
06 · User agents
User agents we see for Chrome Privacy Preserving Prefetch Proxy
| User agent | Share | Last active | Status |
|---|---|---|---|
Chrome Privacy Preserving Prefetch Proxy |
99% | Today | Verified |
Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/30.0 Chrome… |
0.3% | 22 days ago | Verified |
Mozilla/5.0 (Linux; Android 7.0; SM-G928G Build/NRD90M) AppleWebKit/537.36 (KHTML, like Gecko) Chrom… |
0.1% | 7 days ago | Verified |
Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/29.0 Chrome… |
0.1% | 19 days ago | Verified |
07 · Verification
Is it really Chrome Privacy Preserving Prefetch Proxy?
Anyone can copy a user agent. Real Chrome Privacy Preserving Prefetch Proxy requests come from the IP ranges published at gstatic.com/chrome/prefetchproxy/prefetch_proxy_geofeed.
IP addresses we saw from verified Chrome Privacy Preserving Prefetch Proxy requests
| IP range | Share | Last active |
|---|---|---|
66.249.88.0/27 |
27% | Today |
66.249.93.0/27 |
18% | Yesterday |
74.125.215.0/27 |
15% | 8 days ago |
74.125.212.0/27 |
11% | Today |
192.178.8.0/27 |
7.3% | Today |
64.233.173.0/27 |
7.0% | 13 days ago |
66.249.81.0/27 |
6.6% | 2 days ago |
66.249.82.0/27 |
6.3% | Today |
142.250.33.0/27 |
1.6% | Today |
192.42.116.14 |
0.2% | 7 days ago |
Always check against the operator’s current list; ranges change.
FAQ
Questions about Chrome Privacy Preserving Prefetch Proxy
Why does Chrome Privacy Preserving Prefetch Proxy request /.well-known/traffic-advice?
The proxy checks this file to learn whether, and how much, prefetch traffic the site accepts. A missing file causes 404 errors but no harm.
How do I stop Chrome from prefetching my site?
Serve /.well-known/traffic-advice with MIME type application/trafficadvice+json. Set "disallow": true for the prefetch-proxy user agent, or a fraction to throttle.
How can I recognize prefetch requests?
Prefetch requests include the header Sec-Purpose: Prefetch; anonymous-client-ip. Chrome publishes a geofeed of proxy IP addresses.
Last updated Oct 14, 2026