Updated 2026-07-06
What are AI crawlers?
AI crawlers are bots that fetch web pages for AI answer engines and model training. They differ from Googlebot in behavior and intent: many don't execute JavaScript, they fetch less often, and they feed retrieval and training rather than a search index. Deciding whether to allow them is a trade between citation reach and content control.
Definition
AI crawlers are the fetching layer behind generative answer engines. Some feed real-time retrieval — the pages an engine pulls at answer time to cite (Perplexity, ChatGPT with web search). Others feed model training — building the knowledge a model draws on when it answers from memory. The two purposes matter because the decision to allow or block them has different consequences: blocking a retrieval crawler removes you from citations; blocking a training crawler removes you from the model's accumulated knowledge.
AI crawlers vs Googlebot
Googlebot is built for a search index that ranks pages and sends traffic. AI crawlers are built for synthesis: they fetch pages so an engine can quote, summarize, or learn from them, often without sending a click back. Practical differences: many AI crawlers don't execute JavaScript, so client-rendered content reads as empty to them; they fetch less frequently and give up faster; and they identify themselves with distinct user agents that need their own robots rules.
Allow, block, or be selective
The choice is a business decision, not a technical one. Blocking all AI crawlers protects content but removes you from AI answers entirely — no citations, no mentions from retrieval. Many teams split the difference: allow retrieval crawlers (so you can be cited) while blocking training crawlers (so your content isn't used to improve a competitor's model). The trade is covered in Should you block AI crawlers?.
How to check whether AI crawlers can read you
A server-rendered, crawlable page is the baseline. The site audit fetches your pages the way AI crawlers do and reports what blocks citation: JavaScript-dependent content, blocked bots, slow responses, and missing structure.
- AI crawlers feed retrieval (citation) and training (model knowledge) separately.
- Many AI crawlers do not execute JavaScript — client-rendered content is invisible to them.
- Blocking retrieval crawlers removes you from citations; blocking training crawlers removes you from model knowledge.
- Selective allow/block is common: allow citation crawlers, block training crawlers.
Related reading
Site audit for checking retrievability; Should you block AI crawlers? for the decision framework; llms.txt for the proposed index format for LLM crawlers.