What are AI crawlers?

They are bots operated by AI companies that read publicly available web pages. Some collect text to help train future models; others fetch live pages so an AI assistant can cite current information when it answers a question. Many companies run a separate bot for each job — for example OpenAI uses GPTBot for training and OAI-SearchBot for browsing.

Should I block AI crawlers?

It depends, and the tradeoff is real. Blocking training crawlers keeps your content out of model training — but for the crawlers that fetch live sources, blocking them can also remove you from the answers those assistants generate. Decide per bot: you can allow the ones that surface you in AI answers while restricting the ones you only object to for training.

How do I control AI crawlers?

Mainly through robots.txt, where you allow or disallow each bot by its user-agent (GPTBot, Google-Extended, ClaudeBot, and so on). The major AI crawlers publish their user-agent names and state that they respect robots.txt, so per-bot rules are the standard lever.

Glossary · How AI reads content

AI Crawlers

Bots operated by AI companies — like GPTBot, ClaudeBot and Google-Extended — that read the web to train models and to fetch sources for AI answers.

Updated August 20265 min readReviewed by PageLens.ai

Common AI crawlers

GPTBot · OpenAItrain
Google-Extendedtrain
ClaudeBot · Anthropictrain
PerplexityBotfetch
OAI-SearchBotfetch

Some AI crawlers gather training data; others fetch live pages to answer questions.

AI crawlers are the bots that AI companies send out to read the web. They do it for two distinct reasons — to gather text for training models, and to fetch live pages so an assistant can answer with current, cited information.

The two jobs a crawler can have

It is tempting to treat “AI crawler” as one thing, but the purpose matters enormously when you decide how to handle them. A training crawler collects publicly available text that may be used to improve a future model. A fetching crawler (sometimes called a user-agent or search bot) retrieves a page in real time because a person just asked a question and the assistant is gathering sources to answer it.

Training crawlers

Fetching crawlers

Collect text to train future models

Retrieve live pages to answer a query now

e.g. GPTBot, Google-Extended, ClaudeBot

e.g. OAI-SearchBot, PerplexityBot

Blocking removes you from training

Blocking can remove you from the answer

The main ones to know

The crawlers you are most likely to see in your logs come from a handful of companies, and several run more than one bot:

OpenAI. GPTBot reads pages that may help train models; OAI-SearchBotfetches sources for ChatGPT’s browsing.
Google. Google-Extended is the control that governs whether your content is used for Gemini and related AI training.
Anthropic. ClaudeBotcrawls the web on Anthropic’s behalf.
Perplexity. PerplexityBot gathers sources for its answer engine.
Common Crawl. CCBot builds a large public web archive that many AI datasets draw from.

Controlling access — and the tradeoff

The primary control is robots.txt: you allow or disallow each bot by its user-agent, and the major AI crawlers state that they respect it. The decision is not purely technical, though.

Why it matters for visibility

As more discovery moves through AI answers, being readable by the right crawlers becomes part of being findable at all. The honest position is a per-bot one: decide where you genuinely object to training use, but keep the door open for the fetching crawlers that put you in front of people asking questions in your category. If a crawler can’t reach your page, no amount of good content will get you into the answer it builds.

Frequently asked

What are AI crawlers?: They are bots operated by AI companies that read publicly available web pages. Some collect text to help train future models; others fetch live pages so an AI assistant can cite current information when it answers a question. Many companies run a separate bot for each job — for example OpenAI uses GPTBot for training and OAI-SearchBot for browsing.
Should I block AI crawlers?: It depends, and the tradeoff is real. Blocking training crawlers keeps your content out of model training — but for the crawlers that fetch live sources, blocking them can also remove you from the answers those assistants generate. Decide per bot: you can allow the ones that surface you in AI answers while restricting the ones you only object to for training.
How do I control AI crawlers?: Mainly through robots.txt, where you allow or disallow each bot by its user-agent (GPTBot, Google-Extended, ClaudeBot, and so on). The major AI crawlers publish their user-agent names and state that they respect robots.txt, so per-bot rules are the standard lever.