# Googlebot vs GPTBot

Googlebot and GPTBot compared on 11 documented fields, from 18 claims, last verified 2026-09-15.

| Field | Googlebot | GPTBot | Comparison |
| --- | --- | --- | --- |
| cites_sources | yes | not documented | different |
| honours_crawl_delay | no | not_documented | different |
| observed_verified_request_ratio_census | 0.991 | not documented | different |
| publishes_ip_list | yes | yes | same |
| purpose_documented | search | training | different |
| reads_llms_txt | no | not documented | different |
| respects_robots_txt | yes | yes | same |
| robots_txt_fetch_marker | not documented | yes | different |
| separate_search_and_training_tokens | yes | yes | same |
| user_agent_string_full | Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Googlebot/2.1; +http://www.google.com/bot.html) | Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; GPTBot/1.4; +https://openai.com/gptbot | different |
| verifiable_by_rdns | yes | not_documented | different |

## Differences

| Field | Googlebot statement | GPTBot statement |
| --- | --- | --- |
| cites_sources | Google AI Overviews and AI Mode return AI generated responses with links to supporting websites. | not documented |
| honours_crawl_delay | Google does not support the robots.txt Crawl-delay directive for Googlebot. | OpenAI does not publish whether GPTBot honours the robots.txt Crawl-delay directive. |
| observed_verified_request_ratio_census | 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. | not documented |
| purpose_documented | Googlebot crawls pages for Google Search, Google Images, Google Video, Google News, and Discover. | GPTBot crawls content that may be used to train OpenAI generative AI foundation models. |
| reads_llms_txt | Google Search does not use llms.txt files. | not documented |
| robots_txt_fetch_marker | not documented | OpenAI may add a robots.txt marker to the GPTBot user agent string when GPTBot fetches robots.txt files. |
| user_agent_string_full | 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). | GPTBot sends the user agent string Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; GPTBot/1.4; +https://openai.com/gptbot. |
| verifiable_by_rdns | Googlebot requests are verifiable by reverse DNS lookup resolving to googlebot.com, google.com, or googleusercontent.com. | OpenAI does not publish a reverse-DNS verification method for GPTBot. |

## 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/gptbot.json
- https://rattlesnakesbymail.com/observed/googlebot