OpenAI crawlers
Definition
OpenAI crawlers are the automated web agents OpenAI uses to access web content, each with a distinct purpose and user agent. GPTBot collects data that may be used for model training, OAI-SearchBot indexes pages for ChatGPT search, and ChatGPT-User fetches pages in response to a user's live request. Sites can allow or block each independently via robots.txt.
How it works
OpenAI publishes separate user agents for distinct activities. GPTBot crawls the web to gather content that may be used to improve future models. OAI-SearchBot discovers and indexes pages so they can surface as sources in ChatGPT's search experience. ChatGPT-User represents a real-time fetch triggered when a user asks ChatGPT to visit or browse a specific page.
Each agent identifies itself with a documented user-agent string and respects robots.txt directives. Because the purposes differ, site owners can make different decisions for each, for example blocking training collection while permitting search indexing and user-initiated browsing.
Why it matters for AI visibility
The distinction between crawlers is central to AI visibility strategy. Blocking OAI-SearchBot can remove a site from ChatGPT search results, reducing the chance of being cited, while blocking GPTBot only affects potential training use. Treating all OpenAI crawlers identically risks unintentionally cutting off discovery.
Publishers weighing content licensing, traffic, and brand presence should configure robots.txt deliberately, allowing the agents that drive visibility and citation while controlling those tied to training. Clear per-agent rules let a site participate in AI search without conceding all data uses.
Frequently asked questions
What are the main OpenAI crawlers?
The primary ones are GPTBot, which gathers content that may be used for model training; OAI-SearchBot, which indexes pages for ChatGPT search; and ChatGPT-User, which fetches pages when a user asks ChatGPT to browse them.
How do I block or allow OpenAI crawlers?
Use robots.txt with each crawler's documented user-agent string. You can allow or disallow GPTBot, OAI-SearchBot, and ChatGPT-User independently, since they serve different purposes.
Should I block GPTBot?
That depends on your stance on training use. Blocking GPTBot limits content from being used to train future models but does not by itself affect ChatGPT search visibility, which depends on OAI-SearchBot.
Does blocking OpenAI crawlers affect ChatGPT visibility?
Blocking OAI-SearchBot can prevent your pages from being indexed for and cited in ChatGPT search. Blocking only GPTBot affects training data collection, not search visibility, which is why per-agent rules matter.
AI bots
AI bots are the automated crawlers operated by AI companies to fetch web content for training and retrieval. The major AI bots in 2026 are GPTBot and ChatGPT-User (OpenAI), ClaudeBot and anthropic-ai (Anthropic), PerplexityBot, Google-Extended (Gemini), and Bytespider (ByteDance). Whether your robots.txt allows them determines whether your content can be cited inside AI assistants.
OpenAI
OpenAI is an AI research and deployment company best known for ChatGPT, the GPT family of large language models, the o-series reasoning models, and the DALL·E image models. It operates a widely used consumer assistant alongside an API and enterprise products, making it a dominant force in both consumer and business AI.
ChatGPT
ChatGPT is OpenAI's conversational AI assistant, powered by the GPT family of models. It answers questions, writes and edits content, reasons through problems, browses the web, and uses tools. As one of the most widely used mainstream AI assistants, it is a key surface for generative engine optimization (GEO).
llms.txt
llms.txt is a proposed web standard — a markdown-formatted file placed at the root of a website — that gives LLMs and AI tools a curated index of a site's most important content. Modeled on robots.txt and sitemap.xml but designed for LLM comprehension rather than search crawlers, llms.txt is in the early adoption phase as of 2026, with no major AI platform officially committed to consuming it.
AI indexing
AI indexing is the process by which AI assistants — ChatGPT, Claude, Gemini, Perplexity, Grok, and Google AI Overviews — crawl, parse, embed, and store web content so it can be retrieved and cited at inference time. It is the AI-search counterpart to Google's traditional index, and the gateway any page must pass through to be eligible for citation.
AI training data
AI training data is the corpus of text, code, images, and other content used to train large language models. Frontier models like GPT-4o, Claude 4 Sonnet, Gemini 2.5, and Llama 4 are trained on trillions of tokens drawn from web crawls, books, code repositories, and licensed datasets — the composition of which shapes what the model knows, who it cites, and how it represents brands.