Learn what LLM crawlers and AI bots are indexing from your site and how they perform, the content they prioritize, their feature sets, and what they filter out.
If you’re a marketer, you want to know how LLMs work so you can make sure your products and brands are best represented when prospects go to ChatGPT, Perplexity, and other LLMs to research your company.
Table of Contents
Popular AI crawler bots
Below is a fairly complete list of the major LLM crawler bots as of right now (in 2025), and how they work and stack up as far as uses, features, and what set them apart from each other.
| LLM or Company | Crawler Bot Name | Uses |
| Amazon | Amazonbot / Bedrock Crawler | Used for Alexa & Amazon Bedrock |
| Anthropic | ClaudeBot | Crawls for safe, high-quality AI training data |
| Apple | Applebot (and Applebot‑Extended) | Crawls public content; controls AI training use |
| Cohere | Cohere-AI | Web crawler gathering public data for NLP model training |
| Common Crawl | CCBot | Builds open datasets for LLM training |
| Google-Extended crawler | Filters content for Gemini AI training (not search) | |
| Huawei | PanguBot | AI-training crawler for Huawei’s Pangu LLMs |
| Hugging Face | HF Crawler (via datasets) | Aggregates external open data sources |
| LAION | laion-crawler / img2dataset | Collects public multimodal data for models |
| Meta | FacebookBot | Scrapes metadata for link previews and model training |
| Mozilla | DeepSpeech corpus projects | Academic speech corpora partially derived from web |
| OpenAI | GPTBot | Collects public web data for model training |
| OpenAI | ChatGPT-User | Fetches web pages on user request via browsing tools |
| Perplexity | PerplexityBot | Scrapes web for AI answers and real-time retrieval |
| Snowflake | Neevabot | Previously for AI-enhanced search |
| You.com | YouBot / YouSearchBot | Powers You.com’s AI-assisted search |
Popular LLMs using crawlers for training
Here’s what’s happening: The llm bots are using crawlers to collect public content to train their models, along with generating those real-time AI responses you see, and in training assistant tools (examples: Alexa or Siri). The big players use proprietary bots, and the small players (like Common Crawl and LAION) have open datasets.
Some of the usual suspects (think OpenAI, Anthropic, etc.) are always crawling the web for high-quality, frequently updated public content. Why? Simply, It’s good data for them to train their AI models.
Some groups (like Common Crawl, LAION, and Mozilla) are open source and contribute to the broader ecosystem, however the majority operate proprietary systems, often caching results and ignoring JavaScript to access more static content.
Google’s and OpenAI’s user-facing tools are exceptions: they don’t crawl autonomously but rely on external inputs or opt-in content for training and retrieval.
| LLM or Company | What it prioritizes | Open Source | Crawls websites | Caches Previous Searches | Ignores JavaScript |
| Amazon | Public content for voice & AI responses | No | Yes | Yes | Yes |
| Anthropic | High-value content, frequent updates | No | Yes | Yes | Yes |
| Apple | Clean, structured, licensed public pages | No | Yes | Likely Yes | No |
| Cohere | Public, high-quality text; training‑friendly content | No | Yes | Yes | Yes |
| Common Crawl | Large-scale public web archive | Yes | Yes | Yes | Yes |
| Public pages allowed for AI training | No | No | Yes | No | |
| Huawei | Multimedia‑rich, frequently updated, high‑density public content | No | Yes | Yes | Yes |
| Hugging Face | Curated public datasets | Mostly Yes | Partially (via APIs) | Yes | Varies |
| LAION | Images + associated high-quality text | Yes | Yes | Yes | Yes |
| Meta | Public web pages shared on Facebook | No | Yes | Yes | Yes |
| Mozilla | Public spoken/editable text for speech models | Yes | Partially | Yes | Likely Yes |
| OpenAI | High-quality, publicly available, licensed content | No | Yes | Yes | Yes |
| OpenAI | User-requested, relevant, accessible, factual content | No | No | No | Yes |
| Perplexity | Up-to-date Q&A, facts | No | Yes | Likely Yes | Yes |
| Snowflake | Public, licensed search content | No | Yes | Probably Yes | Yes |
| You.com | Real-time relevant search content | No | Yes | Probably Yes | Yes |
What LLM crawlers filter out
Most LLM bots respect robots.txt directives to some extent, using them as the primary filter to avoid crawling restricted content. Many go further by excluding private, paywalled, login-required, or harmful content (with Apple, Anthropic, and OpenAI applying particularly strict filters to protect personal data and avoid unsafe material).
| LLM or Company | What it filters out | Always respects robot.txt |
| Amazon | Respect robots.txt rules only | Yes |
| Anthropic | Harmful, illegal, explicit, violent, unsafe content | Yes |
| Apple | Profane, low-quality, personal data, private login pages | Yes |
| Cohere | Disallowed via robots.txt or server rules | No |
| Common Crawl | Following robots.txt, avoids disallowed content OpenReplay Blog | Yes |
| Content disallowed via Google‑Extended in robots.txt | Yes | |
| Huawei | Private, pay‑walled, restricted or disallowed content | Yes |
| Hugging Face | Varies by dataset | Depends on source |
| LAION | Disallowed content via robots.txt | Yes |
| Meta | Private, login‑only, disallowed via robots.txt | No |
| Mozilla | Private or restricted speech data | Yes |
| OpenAI | Paywalled content, personally identifying information | Yes |
| OpenAI | Blocked, paywalled, private, non-permitted, login-required content | Yes |
| Perplexity | N/A (Some reports say ignores robots.txt) OpenReplay Blog | No |
| Snowflake | Standard disallow via robots.txt | Yes |
| You.com | Disallowed via robots.txt | Likely Yes |
LLM crawler transparency
Transparency among LLM bots varies widely, with lots of major players operating openly about their data practices and crawler behavior. You’ve got some LLM bots that are all about safety. You’ve got others that just aren’t transparent about what their doing to gather data, and even if they are, they aren’t transparent about what they’re doing with it after they gather it.
| LLM or Company | Operates transparently | Defining Feature |
| Amazon | Yes | Enterprise voice crawler for Alexa & Bedrock |
| Anthropic | Yes | Safety-focused, Constitutional AI, alignment-first, limited web access |
| Apple | Partial | Search & Siri crawler with AI‐training opt‑out via robots.txt |
| Cohere | No | Enterprise-focused, text-data crawler, minimal opt‑in transparency |
| Common Crawl | Yes | Open archival crawler trusted for open-source dataset building |
| Yes | Blocking Google-Extended has no effect on your visibility in Google Search | |
| Huawei | No | AI‑training crawler, multimodal LLM data collection, periodic recrawling |
| Hugging Face | Yes | Central dataset hub building community-curated model data |
| LAION | Yes | Open large-scale image-text collection for open LLMs |
| Meta | No | Link preview carbon-copy crawler for speech‑model training |
| Mozilla | Yes | Speech-focused dataset projects with open academic release |
| OpenAI | Yes | Versatile, widely deployed, Reinforcement Learning |
| OpenAI | Yes | Real-time user browsing, no autonomous crawling behavior |
| Perplexity | No | Aggressive real-time scraping for AI answer generation |
| Snowflake | Likely Yes | Privacy-first search-to-AI enhanced index |
| You.com | Yes | On-demand search-fetch crawler for AI assistant |
LLM visibility is as critical as SEO
Now that you’ve seen a little bit of the behavior and priorities of LLM Bots and AI crawlers, you probably have a better idea what’s happening around how they access content and the impact it could have on your business. You probably already sense that optimizing for LLM visibility is as critical as traditional SEO. Now you’ve got a better idea how you might optimize your site for AI-driven search, given how LLM Bots access content. If you need a little help, check out our next steps.
How to make your content visible to LLM crawler bots
If you’re a B2B company trying to navigate the impact of AI search, also known as generative engine optimization (GEO) or answer engine optimization (AEO) and you’re looking for a partner, feel free to reach out to us at On Marketing. We’re an AEO agency dedicated to helping B2B companies show up better on LLMs.