Published on 2025-08-07T06:18:08Z

Meta-ExternalAgent

Meta-ExternalAgent is a web crawler from Meta (formerly Facebook) that collects public web content for two main purposes: to train its artificial intelligence models (like LLaMA) and to build its own independent search capabilities. It can be an aggressive crawler with high request volumes, and its activity does not provide direct benefits to website owners, such as search traffic.

What is Meta-ExternalAgent?

Meta-ExternalAgent is a web crawler operated by Meta, designed to collect and index public web content. Its data is used for training Meta's AI models and for building its independent search infrastructure. The crawler identifies itself in server logs with the user-agent string meta-externalagent/1.1. It functions as part of Meta's AI infrastructure, systematically visiting websites to gather information. The bot focuses on efficiently extracting raw HTML content and has been observed to have aggressive crawl patterns with high request volumes.

Why is Meta-ExternalAgent crawling my site?

Meta-ExternalAgent is visiting your website to collect its diverse public content for use in training Meta's AI systems and to enhance its search capabilities. The crawler prioritizes sites with high information density, frequently updated content, and well-structured data, as these are valuable for language model training. The frequency of visits can be high, with some domains receiving hundreds of requests daily. Your site may be experiencing this crawling because it contains rich textual information that Meta finds valuable for improving its AI models.

What is the purpose of Meta-ExternalAgent?

Meta-ExternalAgent serves two key strategic purposes for Meta. First, it gathers training data for its large language models (LLMs) like LLaMA, which power AI features across its platforms. Second, it contributes to Meta's efforts to develop an independent search engine, which would reduce its reliance on third-party providers. Unlike traditional search engine crawlers that can drive traffic to your site, this bot's activity primarily benefits Meta's internal AI and search development. Any benefit to website owners is indirect, through potential inclusion in AI-generated responses within the Meta ecosystem.

How do I block Meta-ExternalAgent?

If you wish to prevent Meta from using your content for AI training or its search development, you can block the Meta-ExternalAgent crawler. You can add a disallow rule to your robots.txt file.

To block this bot, add the following lines to your robots.txt file:

User-agent: meta-externalagent
Disallow: /

How to verify the authenticity of the user-agent operated by Meta?

Reverse IP lookup technique

To verify user-agent authenticity, you can use host linux command two times with the IP address of the requester.

```
> host IPAddressOfRequest
```
This command returns the reverse lookup hostname (e.g., 4.4.8.8.in-addr.arpa.).

> host ReverseDNSFromTheOutputOfFirstRequest

If the output matches the original IP address and the domain is associated with a trusted operator (e.g., Meta), the user-agent can be considered legitimate.

IP list lookup technique

Some operators provide a public list of IP addresses used by their crawlers. This list can be cross-referenced to verify a user-agent's authenticity. However, both operators and website owners may find it challenging to maintain an up-to-date list, so use this method with caution and in conjunction with other verification techniques.