AI Crawlers Are Already Visiting Your Website
If your website is publicly accessible, AI crawlers are almost certainly visiting it – whether you know it or not. These automated bots, operated by companies like OpenAI, Anthropic, Google, and Perplexity, crawl web content to either train AI models or power real-time AI search features.
For most website owners, the existence of these crawlers raises immediate questions. What are they doing? Should I block them? Will blocking them hurt my visibility? The answers depend on understanding a critical distinction: the difference between training crawlers and search retrieval crawlers.
This guide identifies the major AI crawlers active today, explains what each one does, and provides practical advice for managing them in a way that protects your content while maximising your AI visibility.
The Major AI Crawlers
The AI crawler landscape has expanded significantly since 2023. Here are the most important crawlers you need to know about, grouped by the organisation that operates them.
OpenAI Crawlers
GPTBot (user agent: GPTBot/1.0)
GPTBot crawls websites to collect data for training OpenAI's language models. Content indexed by GPTBot may be used to improve future versions of GPT models. It does not power real-time ChatGPT Search results. GPTBot respects robots.txt directives and can be selectively blocked.
OAI-SearchBot (user agent: OAI-SearchBot/1.0)
OAI-SearchBot retrieves web content in real time to power ChatGPT Search – the feature that allows ChatGPT to browse the web and provide cited, up-to-date answers. Blocking OAI-SearchBot means your content will not appear in ChatGPT search results. This is arguably the most consequential AI crawler for immediate brand visibility.
ChatGPT-User (user agent: ChatGPT-User)
This agent is used when a ChatGPT user directly requests that the model visit a specific URL during a conversation. It represents individual user-initiated browsing rather than systematic crawling.
Anthropic Crawlers
ClaudeBot (user agent: ClaudeBot/1.0)
ClaudeBot is Anthropic's web crawler, used to index content for Claude's knowledge base and features. As Claude continues to expand its web-connected capabilities, ClaudeBot's role in powering real-time responses is growing. Blocking ClaudeBot may reduce your visibility in Claude-powered applications and integrations.
Perplexity Crawlers
PerplexityBot (user agent: PerplexityBot)
PerplexityBot crawls the web to power Perplexity AI's search engine. Perplexity is built entirely around cited, real-time web search, making its crawler directly analogous to a traditional search engine crawler. Every citation in a Perplexity response comes from content that PerplexityBot (or its underlying search infrastructure) has retrieved. Blocking PerplexityBot effectively removes your site from Perplexity results.
Google Crawlers
Google-Extended (user agent: Google-Extended)
Google-Extended is the crawler Google uses to collect data for training its Gemini models and improving AI-powered features. It is separate from the standard Googlebot crawler used for search indexing. Blocking Google-Extended does not affect your traditional Google search rankings – it only affects whether your content is used for AI model training. However, Google AI Overviews (the AI-generated summaries that appear in search results) draw from Google's standard search index, not from Google-Extended. This means blocking Google-Extended does not remove you from AI Overviews.
Googlebot (user agent: Googlebot)
The standard Googlebot is worth mentioning because Google AI Overviews use the regular search index. If you are indexed by Googlebot, your content is eligible to appear in AI Overviews. Blocking Googlebot removes you from both traditional search results and AI Overviews.
Other Notable Crawlers
Bytespider (user agent: Bytespider)
Operated by ByteDance (the parent company of TikTok), Bytespider crawls websites for AI model training and powers various ByteDance AI products. It is one of the most aggressive AI crawlers by volume, and many website owners choose to block it due to its high crawl rate and limited transparency about data usage.
CCBot (user agent: CCBot)
CCBot is the crawler for Common Crawl, a non-profit that maintains one of the largest open web archives. Common Crawl data has been used to train numerous AI models, including early versions of GPT. While Common Crawl itself is a research resource, the downstream use of its data for commercial AI training has led some publishers to block CCBot.
Applebot-Extended (user agent: Applebot-Extended)
Apple's extended crawler gathers data for Apple's AI features, including Apple Intelligence. As Apple continues to integrate AI into its products, this crawler's importance may grow.
Training vs Search Retrieval: Why the Distinction Matters
The single most important concept in AI crawler management is the distinction between training and search retrieval.
Training Crawlers
Training crawlers (GPTBot, Google-Extended, Bytespider, CCBot) collect data that is used to build or improve AI models. Your content becomes part of the model's knowledge base – a permanent contribution to a dataset that powers commercial AI products. Many publishers have legitimate concerns about this, particularly around intellectual property, compensation, and consent.
Blocking training crawlers is a defensible choice. It does not directly affect your real-time AI search visibility because these crawlers do not power live search features.
Search Retrieval Crawlers
Search retrieval crawlers (OAI-SearchBot, PerplexityBot, ChatGPT-User) fetch your content in real time to generate cited, up-to-date answers. This is functionally similar to how Googlebot indexes content for Google Search. Blocking search retrieval crawlers directly removes your content from AI search results – a potentially significant loss of visibility.
The Recommended Approach
For most businesses seeking to maximise AI visibility while maintaining control over their content, the recommended approach is:
- Allow search retrieval crawlers (OAI-SearchBot, PerplexityBot, ChatGPT-User, ClaudeBot)
- Evaluate training crawlers on a case-by-case basis (GPTBot, Google-Extended, Bytespider, CCBot)
- Block crawlers from organisations where you see no business benefit and have concerns about data usage (Bytespider is a common candidate)
Our AI Bot Manager tool helps you implement these configurations without editing code, and our robots.txt builder generates the correct directives for each crawler.
How to Configure robots.txt for AI Crawlers
The robots.txt file remains the primary mechanism for controlling AI crawler access. Here is a practical example of a configuration that allows search retrieval while blocking training:
# Allow AI search crawlers
User-agent: OAI-SearchBot
Allow: /
User-agent: PerplexityBot
Allow: /
User-agent: ChatGPT-User
Allow: /
User-agent: ClaudeBot
Allow: /
# Block training crawlers
User-agent: GPTBot
Disallow: /
User-agent: Google-Extended
Disallow: /
User-agent: Bytespider
Disallow: /
User-agent: CCBot
Disallow: /
Important caveats:
- robots.txt is a voluntary protocol. Well-behaved crawlers respect it, but compliance is not guaranteed for all bots.
- Blocking a crawler does not remove content that has already been crawled and indexed. If GPTBot has already ingested your content, blocking it only prevents future crawling.
- Some crawlers (like PerplexityBot) may also use underlying search engine indices (such as Bing), so blocking PerplexityBot alone may not completely remove your content from Perplexity results if it is available via those indices.
Crawl-Delay and Rate Limiting
AI crawlers can be aggressive. Bytespider, in particular, has been reported to make extremely frequent requests that can strain server resources. The Crawl-delay directive allows you to request that a crawler wait a specified number of seconds between requests:
User-agent: Bytespider
Crawl-delay: 10
User-agent: ClaudeBot
Crawl-delay: 5
Not all crawlers honour the Crawl-delay directive – it is not part of the original robots.txt specification, though many crawlers support it in practice. For server protection, you may also want to implement rate limiting at the server or CDN level, particularly for crawlers that do not respect robots.txt directives.
Beyond robots.txt: Additional Control Mechanisms
The noai and noimageai Meta Tags
Some publishers use meta tags to signal that their content should not be used for AI training:
<meta name="robots" content="noai, noimageai">
Support for these tags is inconsistent across AI companies, but they represent an emerging standard that may gain broader adoption.
HTTP Headers
The X-Robots-Tag HTTP header can also be used to communicate AI-related directives, particularly for non-HTML content (PDFs, images, etc.) where meta tags are not available.
llms.txt
The llms.txt standard is a newer convention that provides AI-specific guidance in a dedicated file. Unlike robots.txt (which controls access), llms.txt provides contextual information about your site that helps AI systems understand and accurately represent your content. We cover this in detail in our GEO service offering.
Practical Management Advice
Managing AI crawlers does not need to be complicated, but it does need to be deliberate. Here is a practical checklist:
- Audit your current robots.txt – Check whether you are inadvertently blocking search retrieval crawlers or allowing training crawlers you would prefer to block.
- Review your server logs – Identify which AI crawlers are visiting your site, how frequently, and which pages they are accessing. This data informs your decisions.
- Implement per-bot directives – Do not use blanket rules. Configure each major AI crawler individually based on whether it serves training or search purposes.
- Monitor crawl impact – Watch for unusual server load from aggressive AI crawlers and implement crawl-delay or rate limiting as needed.
- Stay current – New AI crawlers appear regularly. Review your configuration quarterly to account for new bots and changed behaviours.
- Consider your business model – A content publisher may have very different crawler management priorities than an ecommerce business or a service provider. Tailor your approach to your specific situation.
Our technical SEO team works with businesses to implement and maintain AI crawler configurations as part of a broader Generative Engine Optimisation strategy. The technical details matter, but they should serve your business objectives, not the other way around.
Need help managing AI crawlers for your website? Get in touch to discuss a crawler management strategy tailored to your business goals.