What is Chrome Privacy Preserving Prefetch?

Chrome Privacy Preserving Prefetch is a bot in the link preview bots category, operated by Google.

Bot name
Chrome Privacy Preserving Prefetch
Operator
Google
Type
Bot
Respects robots.txt
Not confirmed
robots.txt user agent
ChromePrivacyPreservingPrefetch
Signs requests (Web Bot Auth)
No

About Chrome Privacy Preserving Prefetch

Chrome Privacy Preserving Prefetch loads pages from Google search results ahead of a click, through a proxy that hides the user's IP address, so the page opens faster.

Link preview bots fetch a page when someone shares its URL in a chat app or social network, to build the preview card. Blocking them breaks your link previews, so keep them allowed but leave them out of analytics and ad requests.

Chrome Privacy Preserving Prefetch user agent

Anyone can copy a user agent string. Transfon Security also checks where each request comes from, so a request that claims to be a known crawler but comes from the wrong network is treated as a fake, not as the real crawler.

How to block Chrome Privacy Preserving Prefetch in robots.txt

We have not confirmed whether Chrome Privacy Preserving Prefetch follows robots.txt. Add a rule, then check your logs to see that it stopped. robots.txt is a plain text file at the root of your domain, such as https://example.com/robots.txt.

Block Chrome Privacy Preserving Prefetch from the whole site

User-agent: ChromePrivacyPreservingPrefetch
Disallow: /

Block Chrome Privacy Preserving Prefetch from some folders

User-agent: ChromePrivacyPreservingPrefetch
Disallow: /private/
Disallow: /search

Allow Chrome Privacy Preserving Prefetch only on some folders

User-agent: ChromePrivacyPreservingPrefetch
Allow: /blog/
Disallow: /

Allow Chrome Privacy Preserving Prefetch and block other crawlers

User-agent: ChromePrivacyPreservingPrefetch
Allow: /

User-agent: *
Disallow: /

Things to know

  • Each host needs its own file. Rules on www.example.com do not apply to shop.example.com.
  • A crawler obeys only the most specific group that names it. Once you add a User-agent: ChromePrivacyPreservingPrefetch group, Chrome Privacy Preserving Prefetch ignores your User-agent: * rules, so repeat any that should still apply.
  • The user agent name is not case sensitive. We take ChromePrivacyPreservingPrefetch from Chrome Privacy Preserving Prefetch's user agent; check Google's own documentation if it publishes a different robots.txt name.
  • Crawlers cache robots.txt, so changes can take up to a day to apply. Disallow stops crawling but does not remove pages already collected or indexed.

Limits of robots.txt

  1. Chrome Privacy Preserving Prefetch may not follow the rule. robots.txt is a request that nothing enforces, and we have not confirmed that Chrome Privacy Preserving Prefetch follows it. Check your logs after adding a rule.
  2. The user agent could be fake. robots.txt matches the name a request claims. Anyone can send Chrome Privacy Preserving Prefetch's user agent, and a scraper using it is not bound by Google's robots.txt policy. Only checking the source network tells a real Chrome Privacy Preserving Prefetch from a fake one.

Treat robots.txt as a statement of your policy, and enforce it where requests arrive.

Who should care about Chrome Privacy Preserving Prefetch

Publishers

Chrome Privacy Preserving Prefetch fetches pages when your links are shared or syndicated. Keep it allowed so previews and feeds work, but leave it out of page views and ad requests.

Transfon Security for publishers

Media buyers and advertisers

When ads or posts are shared, Chrome Privacy Preserving Prefetch fetches the landing page. Those hits are not clicks, so keep them out of campaign reports.

Transfon Security for advertisers

E-commerce

Product links shared in chats and feeds are fetched by Chrome Privacy Preserving Prefetch. Keep it allowed so previews show the right image and price.

Transfon Security for e-commerce

SaaS and APIs

Allow Chrome Privacy Preserving Prefetch on public pages so shared links preview well, and keep it off the app.

Transfon Security for SaaS and APIs

Block Chrome Privacy Preserving Prefetch with Transfon Security

robots.txt is a request, not an enforcement. Transfon Security shows Chrome Privacy Preserving Prefetch by name in the Top Bots report, so you can see how often it visits and which pages it reads. Block or allow it with a User Agent rule, or slow it down with a rate limit decision rule.

Transfon Security

Control Chrome Privacy Preserving Prefetch on your site

  • See every Chrome Privacy Preserving Prefetch visit and the pages it reads
  • Spot bots that fake trusted crawler names
  • Block, allow or rate limit Chrome Privacy Preserving Prefetch with one rule
  • Works with or without robots.txt support

Frequently asked questions

What is Chrome Privacy Preserving Prefetch?

Chrome Privacy Preserving Prefetch is a bot in the link preview bots category, operated by Google. Chrome Privacy Preserving Prefetch loads pages from Google search results ahead of a click, through a proxy that hides the user's IP address, so the page opens faster.

Does Chrome Privacy Preserving Prefetch respect robots.txt?

We have not confirmed whether Chrome Privacy Preserving Prefetch follows robots.txt. Add a robots.txt rule, then check your logs to see that it stopped, and block it by user agent if it did not.

How do I block Chrome Privacy Preserving Prefetch?

Add "User-agent: ChromePrivacyPreservingPrefetch" followed by "Disallow: /" to the robots.txt file at the root of your site. To enforce it, block requests whose user agent contains "ChromePrivacyPreservingPrefetch" at your WAF. In Transfon Security that is one User Agent block rule.

Is robots.txt enough to block Chrome Privacy Preserving Prefetch?

No. robots.txt is voluntary, so Chrome Privacy Preserving Prefetch may not follow it, and anyone can send Chrome Privacy Preserving Prefetch's user agent, so a fake Chrome Privacy Preserving Prefetch ignores your rule. Enforce the rule where requests arrive, at your WAF, and check the source network.

Should I block Chrome Privacy Preserving Prefetch?

Link preview bots fetch a page when someone shares its URL in a chat app or social network, to build the preview card. Blocking them breaks your link previews, so keep them allowed but leave them out of analytics and ad requests.

Related bots

All link preview bots · Full bot directory

See Which Bots Visit Your Site

Transfon Security identifies every bot in this directory in your traffic reports, flags fake search crawlers, and lets you allow, block or rate limit each bot.

Stay ahead of the publishing curve

Privacy, security, monetization, and performance insights. A few emails a month, no spam.

By subscribing you agree to our privacy policy.