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

Screaming Frog SEO Spider

Screaming Frog SEO Spider is not an automated bot but a widely used desktop application for conducting technical SEO audits. Its user-agent appears in your logs when an individual—such as your own SEO team, an agency, or a competitor—is actively crawling your site with the tool. It is used to find issues like broken links, duplicate content, and other technical problems that can affect search engine rankings. Its presence indicates a direct interest in your site's technical health.

What is Screaming Frog SEO Spider?

Screaming Frog SEO Spider is a professional website crawler and technical SEO audit tool. It is a desktop application that crawls websites in the same way a search engine bot does, collecting data on page elements, errors, and other SEO-related issues. The tool typically identifies itself in server logs with the user-agent string Screaming Frog SEO Spider/[version number], although users can configure it to use other user-agents. It is capable of rendering JavaScript-heavy pages to discover dynamically generated content.

Why is Screaming Frog SEO Spider crawling my site?

The Screaming Frog SEO Spider is crawling your website because someone is actively analyzing it for technical issues or opportunities. This could be your own marketing team, an SEO agency you have hired, or even a competitor researching your site's structure. The crawler is not automated; each crawl is manually initiated by a user of the desktop application. The user determines the scope and frequency of the crawl. The tool looks for issues like broken links, redirect chains, and duplicate content.

What is the purpose of Screaming Frog SEO Spider?

The purpose of the Screaming Frog SEO Spider is to help SEO professionals, webmasters, and digital marketers identify technical issues that could be harming their search engine rankings and user experience. The comprehensive data it collects allows users to find broken links, analyze page titles and meta descriptions, discover duplicate content, and generate XML sitemaps. For website owners, having your site crawled by this tool is often beneficial, as it usually leads to improvements in your site's performance in search engines.

How do I block Screaming Frog SEO Spider?

To prevent users from crawling your site with the Screaming Frog SEO Spider, you can add a disallow rule to your robots.txt file. Note, however, that users of the tool can configure it to ignore robots.txt or to use a different user-agent, which would bypass this block.

To block the default user-agent, add the following lines to your robots.txt file:

User-agent: Screaming Frog SEO Spider
Disallow: /

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

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., Screaming Frog), 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.