# ChatGPT-User vs Googlebot

ChatGPT-User and Googlebot compared on 10 documented fields, from 19 claims, last verified 2026-09-15.

| Field | ChatGPT-User | Googlebot | Comparison |
| --- | --- | --- | --- |
| cites_sources | not_documented | yes | different |
| honours_crawl_delay | not_documented | no | different |
| observed_verified_request_ratio_census | not documented | 0.991 | different |
| publishes_ip_list | yes | yes | same |
| purpose_documented | user_fetch | search | different |
| reads_llms_txt | not_documented | no | different |
| respects_robots_txt | partial | yes | different |
| separate_search_and_training_tokens | not_documented | yes | different |
| user_agent_string_full | Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ChatGPT-User/1.0; +https://openai.com/bot | Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Googlebot/2.1; +http://www.google.com/bot.html) | different |
| verifiable_by_rdns | not_documented | yes | different |

## Differences

| Field | ChatGPT-User statement | Googlebot statement |
| --- | --- | --- |
| cites_sources | OpenAI does not publish whether ChatGPT responses cite pages fetched by ChatGPT-User. | Google AI Overviews and AI Mode return AI generated responses with links to supporting websites. |
| honours_crawl_delay | OpenAI does not publish whether ChatGPT-User honours the robots.txt Crawl-delay directive. | Google does not support the robots.txt Crawl-delay directive for Googlebot. |
| observed_verified_request_ratio_census | not documented | Googlebot requests to Rattlesnakes By Mail matched Google's published IP ranges on 108 of 109 requests between 2026-09-13T20:00Z and 2026-09-15T09:00Z. Googlebot's first request to Rattlesnakes By Mail in that window was /robots.txt at 2026-09-14T11:53:00Z. |
| purpose_documented | ChatGPT-User visits web pages for user actions in ChatGPT and in Custom GPTs. | Googlebot crawls pages for Google Search, Google Images, Google Video, Google News, and Discover. |
| reads_llms_txt | OpenAI does not publish whether ChatGPT-User reads llms.txt files. | Google Search does not use llms.txt files. |
| respects_robots_txt | ChatGPT-User fetches pages in response to user actions in ChatGPT, and OpenAI states that robots.txt rules may not apply to ChatGPT-User fetches. | Googlebot obeys robots.txt rules when crawling automatically. |
| separate_search_and_training_tokens | OpenAI does not document ChatGPT-User as a search or training opt-out token. | Google separates Search crawling under the Googlebot token from Gemini training under the Google-Extended token. |
| user_agent_string_full | ChatGPT-User sends the user agent string Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ChatGPT-User/1.0; +https://openai.com/bot. | Googlebot sends the user agent string Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Googlebot/2.1; +http://www.google.com/bot.html). |
| verifiable_by_rdns | OpenAI does not publish a reverse-DNS verification method for ChatGPT-User. | Googlebot requests are verifiable by reverse DNS lookup resolving to googlebot.com, google.com, or googleusercontent.com. |

## Sources

- https://developers.google.com/crawling/docs/crawlers-fetchers/verifying-googlebot
- https://developers.google.com/search/blog/2019/07/a-note-on-unsupported-rules-in-robotstxt
- https://developers.google.com/search/docs/appearance/ai-features
- https://developers.google.com/search/docs/crawling-indexing/google-common-crawlers
- https://developers.google.com/search/docs/fundamentals/ai-optimization-guide
- https://developers.google.com/static/crawling/ipranges/common-crawlers.json
- https://developers.openai.com/api/docs/bots
- https://openai.com/chatgpt-user.json
- https://rattlesnakesbymail.com/observed/googlebot