Overview: All AI crawlers at a glance
Every major AI platform operates its own web crawlers to collect content for training, knowledge updates or real-time search. These crawlers are indistinguishable from normal users — they only identify themselves via their user agent string and respect robots.txt.
Core principle for all crawlers: They all respect robots.txt, read only HTML source without JavaScript rendering and prefer technically clean, fast websites. The differences lie in crawl frequency, purpose and the degree of transparency each provider offers.
GPTBot — ChatGPT (OpenAI)
GPTBot
GPTBot is the best-known and most thoroughly documented AI crawler. OpenAI officially introduced it in August 2023 and publishes both a documentation page and the current IP address ranges of the crawler.
GPTBot crawls for two purposes: training future GPT models and updating the knowledge of already trained models. Crawl frequency is moderate compared to Googlebot — important pages are visited on a cycle of weeks to months.
robots.txt control: User-agent: GPTBot — fully supported. OpenAI reliably respects disallow rules.
ClaudeBot — Claude (Anthropic)
ClaudeBot
ClaudeBot is Anthropic's crawler for the Claude language model. It operates on the same basic principles as GPTBot: reading HTML source, respecting robots.txt, no JavaScript rendering.
A distinctive feature of ClaudeBot is its focus on contextual understanding — Anthropic places great emphasis on Claude understanding relationships and nuances, not just retrieving facts. This means well-structured, content-rich pages are particularly valued by ClaudeBot.
robots.txt control: User-agent: ClaudeBot — fully supported.
PerplexityBot — Perplexity AI
PerplexityBot
PerplexityBot differs from GPTBot and ClaudeBot in one important respect: Perplexity is primarily a search engine with AI answers — not a pure chatbot system. This means PerplexityBot crawls more actively and more frequently than the training crawlers of other platforms.
Perplexity cites sources directly in its answers and links to the original pages. A citation by Perplexity is therefore particularly valuable — it brings actual clickable traffic to your website. Anyone who wants to appear as a source on Perplexity must allow PerplexityBot to crawl and have technically sound, citable pages.
robots.txt control: User-agent: PerplexityBot — respected.
Google-Extended — Gemini & AI Overviews
Google-Extended
Google-Extended is a separate crawler from Google for AI-specific purposes — it is distinct from Googlebot which crawls for classic Google Search. Google-Extended collects data for training Gemini and for Google AI Overviews (the AI answers that appear at the very top of Google Search).
What makes Google-Extended special: it can be controlled separately from Googlebot. Anyone who does not want Google using their content for AI training can block Google-Extended while Googlebot continues crawling for regular search. This has no direct influence on Google ranking.
robots.txt control: User-agent: Google-Extended — fully supported, controllable independently of Googlebot.
xAI-Bot / Grok — Grok (xAI)
xAI-Bot / Grok
Grok is the AI model from xAI, Elon Musk's AI company, and is primarily integrated into the X platform (formerly Twitter). The associated web crawler identifies itself with the user agent "xAI-Bot" and crawls the public web for training and knowledge updates.
Compared to other crawlers, xAI is least transparent: there is less official documentation, no published IP address ranges and less clear communication about crawling purpose. Grok nevertheless has a growing user base — especially among X users.
A distinctive feature of Grok: it has real-time access to X posts and can therefore incorporate information from social media directly into answers — independently of web crawling.
robots.txt control: User-agent: xAI-Bot — respected according to current knowledge.
Direct comparison: all crawlers in one table
| Crawler | User agent | JS rendering | Crawl freq. | Source links | Transparency | robots.txt |
|---|---|---|---|---|---|---|
| GPTBot | GPTBot | No | Weeks–months | No | High | Yes |
| ClaudeBot | ClaudeBot | No | Weeks–months | No | Medium | Yes |
| PerplexityBot | PerplexityBot | No | More frequent | Yes | Medium | Yes |
| Google-Extended | Google-Extended | Partial | Regular | Yes (AI Overviews) | High | Yes |
| xAI-Bot (Grok) | xAI-Bot | No | Unknown | Partial | Low | Yes |
Which strategy is right for you?
Maximum AI visibility — allow all
Anyone who wants to be cited in as many AI answers as possible allows all crawlers. This is the most sensible strategy for public websites with informational content, service providers, blogs and tools.
Selective — prioritise Perplexity
Anyone who primarily wants to gain clickable traffic from AI sources should prioritise Perplexity. Since Perplexity embeds source links directly in answers, a citation by PerplexityBot brings actual traffic — unlike GPTBot or ClaudeBot where the source is usually not directly linked.
Block training, allow search
Anyone who does not want their content used for AI training but wants to appear in search results and AI answers can block GPTBot and ClaudeBot while allowing PerplexityBot and Google-Extended.
Block all AI crawlers
For websites with copyrighted, paid or sensitive content it may make sense to block all AI crawlers. This is a conscious decision against AI visibility — but sometimes the right one.
Ready-made robots.txt templates
Allow all AI crawlers
Block training crawlers only
Block all AI crawlers
- Make a conscious decision: which AI crawlers should have access?
- Check robots.txt for correct user agent names — capitalisation matters
- Test robots.txt with a validator after changes
- Add sitemap link to robots.txt
- TTFB under 800ms — so all crawlers can fully read the page
Which AI crawlers have access to your website?
AI-Ready Check analyses in seconds whether GPTBot, ClaudeBot, PerplexityBot and Google-Extended are correctly configured — free, no account needed.
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