ChatGPT-User
OpenAI operates ChatGPT-User, a fetcher that may visit a page when a ChatGPT or Custom GPT user asks a question, and notes ChatGPT users may reach external applications via GPT Actions. OpenAI states it does no automatic crawling. Because a user initiates each request, robots.txt rules may not apply; no robots.txt token is named. Verification uses OpenAI's IP range file.
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ChatGPT-User/1.0; +https://openai.com/botWhat ChatGPT-User does
Logs show a user-agent string that OpenAI labels as the full string: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; ChatGPT-User/1.0; +https://openai.com/bot. Each request corresponds to a person asking ChatGPT or a Custom GPT something that leads the assistant to open a page. OpenAI also mentions, under the same agent, that ChatGPT users may interact with external applications via GPT Actions. OpenAI is explicit that ChatGPT-User is not used for crawling the web in an automatic fashion, so a site owner should expect fetches tied to user prompts rather than systematic traversal of a site.
The category is user-triggered fetch, and OpenAI's documentation states that because these actions are initiated by a user, robots.txt rules may not apply. The docs also say ChatGPT-User is not used to decide whether content may appear in Search; OAI-SearchBot is the robots.txt token for managing Search opt-outs and automatic crawl, and GPTBot is the other token the page names. OpenAI does not present ChatGPT-User itself as a robots.txt control token. Blocking it at the server level stops ChatGPT from reading pages on request, which affects on-demand answers rather than search inclusion.
For verification OpenAI publishes chatgpt-user.json at openai.com. The file holds a creationTime and a prefixes array of ipv4Prefix entries. OpenAI documents no reverse-DNS method for this agent and says nothing about whether it executes JavaScript, so both remain undocumented. Refresh the file on a schedule; the creationTime field records when OpenAI generated the copy you hold, and an address outside the current list is not the documented agent.
Operator note. The documentation states: "Because these actions are initiated by a user, robots.txt rules may not apply." It also states: "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." The documentation does not note that the version number may change, and it does not present ChatGPT-User as a robots.txt control token; the only robots.txt tags it names are OAI-SearchBot and GPTBot. The documentation does not say whether ChatGPT-User executes JavaScript.
Controlling ChatGPT-User with robots.txt
Use the token undocumented in robots.txt. OpenAI documents limits on how this bot applies robots.txt; see the operator note.
User-agent: undocumented
Disallow: /User-agent: undocumented
Allow: /Verifying a request is really ChatGPT-User
Anyone can put ChatGPT-User in a User-Agent header. OpenAI publishes IP ranges for ChatGPT-User at https://openai.com/chatgpt-user.json. No reverse-DNS method is documented.
OpenAI publishes a machine-readable list. Our probe read it on 2026-09-06; the file's own creation time was 2026-09-04.
- Prefixes
- 207
- IPv4
- 207
- IPv6
- 0
First entries at fetch time: 104.208.184.192/28, 104.210.139.192/28, 104.210.139.224/28
SHA-256 of the fetched body: d9e16f6d00d8ce95dd4fc732d0ba3ec8efb2bd9181d660754b4c5a2bf24544df
Common questions
Should I block ChatGPT-User?
Blocking it prevents ChatGPT and Custom GPTs from fetching your pages when a user asks about them. OpenAI also lists GPT Actions, which let ChatGPT users interact with external applications, under the same agent. A block does not control search inclusion; OpenAI directs Search opt-outs to OAI-SearchBot. Since robots.txt may not apply to user-initiated requests, a block would need enforcement by IP or user-agent at the server.
Does ChatGPT-User respect robots.txt?
Only partly. OpenAI's documentation says that because these actions are initiated by a user, robots.txt rules may not apply, and the page names only OAI-SearchBot and GPTBot as robots.txt tags. Treat ChatGPT-User as a fetcher that may read a page regardless of robots.txt.
How do I verify ChatGPT-User?
Match the source IP against OpenAI's published list at openai.com/chatgpt-user.json, a JSON object with a creationTime and a prefixes array of ipv4Prefix values. OpenAI documents no reverse-DNS check for this agent.
Sources
Every fact on this page was checked against OpenAI's own documentation, listed below, and re-checked by a second reviewer before publication. Reviewed September 2026.
Related crawlers
This registry documents how operators describe their own bots so site owners can identify and control them. It does not publish third-party IP lists or guess at undocumented behaviour. To see how your own site responds to automated visitors, the bot detection scanner reads a URL's live response and names the protection it finds.