AI crawler · OpenAI · Fetches when a user asks

ChatGPT-User: what it is, its user agent, and how to block it

ChatGPT-User is OpenAI's fetcher for user requests. Fetches a page when a ChatGPT user or Custom GPT asks for it, including GPT Actions. Not used for automatic crawling. In our 13 October 2026 study, 222 of 2,332 live top sites with readable robots.txt rules (9.5%) disallow ChatGPT-User. Part of the AI crawler list.

What ChatGPT-User does

Operator: OpenAI. Job: Fetches when a user asks. Partly obeys robots.txt.

“Because these actions are initiated by a user, robots.txt rules may not apply. ChatGPT-User is not used to determine whether content may appear in Search. Please use OAI-SearchBot in robots.txt for managing Search opt outs and automatic crawl.”

OpenAI's ChatGPT-User documentation Published IP ranges (JSON)

ChatGPT-User user agent

robots.txt token: ChatGPT-User (matched case-insensitively).

Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ChatGPT-User/1.0; +https://openai.com/bot

robots.txt: allow or block ChatGPT-User

Allow

User-agent: ChatGPT-User
Allow: /

Block

User-agent: ChatGPT-User
Disallow: /

Affects AI answers and citations. Blocking it refuses the fetch OpenAI makes when a user asks its assistant to read your page. OpenAI says robots.txt may not apply to these user-triggered fetches, so a Disallow may change nothing.

Once a group names ChatGPT-User, it ignores your User-agent: * rules, so copy any paths you still want blocked into it.

How many top sites block ChatGPT-User

Disallow ChatGPT-User in robots.txt

9.5%

222 of 2,332 sites

In our 13 October 2026 study, 222 of 2,332 live top sites with readable robots.txt rules (9.5%) disallow ChatGPT-User.

Sample: Tranco top 5,000, tested once on 13 October 2026 from one Indian fixed-line connection. The robots.txt share counts live sites (home page 2xx) whose rules we could read, as on the AI visibility hub. Method and CSV in the study.

Check your own site

The AI crawler checker reads your robots.txt the way ChatGPT-User does and tests what your firewall returns. To write the rules, use the AI robots.txt generator.

Check your page: free, about 20 seconds, no sign-in

What it checks

robots.txt for ChatGPT-User: Finds the group ChatGPT-User obeys under RFC 9309 and the rule that decides your page.
What your CDN lets through: Requests the page as OAI-SearchBot, PerplexityBot and Claude-SearchBot and compares the answers with a browser request.
Content without JavaScript: AI crawlers don't run JavaScript. The audit checks how much of the page is in the raw HTML.

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Questions

What is ChatGPT-User?+

ChatGPT-User is OpenAI's fetcher for user requests. Fetches a page when a ChatGPT user or Custom GPT asks for it, including GPT Actions. Not used for automatic crawling.

What is ChatGPT-User's user agent?+

OpenAI documents it as: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ChatGPT-User/1.0; +https://openai.com/bot. Match on the token ChatGPT-User, since version numbers change.

How do I block ChatGPT-User?+

Add "User-agent: ChatGPT-User" followed by "Disallow: /" to your robots.txt. Partly obeys robots.txt, per OpenAI.

Does blocking ChatGPT-User affect AI search citations?+

Blocking it refuses the fetch OpenAI makes when a user asks its assistant to read your page. OpenAI says robots.txt may not apply to these user-triggered fetches, so a Disallow may change nothing.

How many websites block ChatGPT-User?+