Google-Agent user agent

Definition: As of 17 October 2026, Google-Agent is a user-agent identifier for agents hosted on Google infrastructure that browse the web and perform actions upon user request. Google lists it among its user-triggered fetchers.

Key facts

• Google's user-triggered fetcher documentation publishes mobile and desktop HTTP user-agent strings containing Google-Agent.
• Google's crawler overview defines fetchers as programs that typically make a single request on behalf of a user.
• Google's verification documentation supports checking a request's source IP address against published IP ranges.
• Google's Web Bot Auth guide says a subset of Google-Agent requests carry cryptographic signatures identifying https://agent.bot.goog.

What does the token look like?

Google's crawler overview lists the HTTP User-Agent request header as an identifier for its clients. Its Google-Agent listing gives this desktop string:

Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko; compatible; Google-Agent; +https://developers.google.com/crawling/docs/crawlers-fetchers/google-agent) Chrome/W.X.Y.Z Safari/537.36

The same listing gives this mobile string:

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; Google-Agent; +https://developers.google.com/crawling/docs/crawlers-fetchers/google-agent)

Both forms contain the Google-Agent token and a Google documentation URL. The documented purpose covers browsing and performing actions requested by a user. Google associates these requests with the dedicated user-triggered-agents.json IP range file.

How does robots.txt apply?

A robots.txt file supplies rules for automated clients accessing a website. Google's fetcher documentation says user-triggered fetchers generally ignore those rules because a user requests the fetch. This category includes Google-Agent.

Google's crawler overview separately classifies Googlebot among common crawlers, which always respect robots.txt rules for automatic crawls. Website access policies therefore need to account for the documented category of the requesting client. The Google-Agent token identifies user-directed agent activity within this classification.

How can a website verify the request?

Google warns in its fetcher listing that user-agent strings can be spoofed. A matching header alone is insufficient to authenticate a request.

Google's verification instructions describe matching the source IP address against published ranges, including a separate list for user-triggered agents. For manual verification, Google describes finding the hostname associated with the source IP address through a reverse DNS lookup. The returned domain must be checked, and a forward DNS lookup of that hostname must return the original IP address.

Web Bot Auth is an experimental protocol for authenticating signed bot requests. Google's implementation guide identifies signed Google-Agent traffic as https://agent.bot.goog. Google recommends retaining IP-based verification because signing covers only a subset of requests.

Related terms

• Googlebot
• Google Read Aloud user agent
• robots.txt

FAQ

Where can I check Google-Agent IP ranges?

Google's fetcher documentation points to user-triggered-agents.json. Compare the request's source IP address with that published list.

Can I authenticate every request with Web Bot Auth?

Google's experimental authentication guide says only a subset of Google-Agent requests are signed. Retain the documented IP-based verification fallback.

Sources

1. Google, "List of Google user-triggered fetchers", 19 August 2026
2. Google, "Overview of Google crawlers and fetchers (user agents)", 12 June 2026
3. Google, "Verify requests from Google crawlers and fetchers", 20 March 2026
4. Google, "Authenticate requests with Web Bot Auth (experimental)", 13 October 2026

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