SEO4Ajax web crawler

What is s4a?

If you've come to this page, then you're probably interested in learning more about our web crawler, identified as user-agent "s4a"

The SEO4Ajax crawler runs on a cloud computing platform that consists of several thousand computers, which is why you may see our web crawler access your site from many different IP addresses.

Why is s4a crawling my website?

"s4a" is the user-agent used by the crawler of SEO4Ajax. SEO4Ajax allows its users to run web crawls on their site in order to refresh cached pages. So, if s4a is crawling your website, it means that one or more SEO4Ajax users created a web crawl that went (eventually) to your website.

Help us crawl your website properly

If you feel that s4a is crawling your website too quickly, please let us know what an appropriate crawl rate is for you. If you'd like us to stop crawling your website, the best thing to do is to stop the crawl if you are a user of SEO4Ajax. Otherwise, you can contact us at

Blocking us by IP address

Blocking our web crawler by IP address will not work. Due to the distributed nature of our infrastructure, we have numerous constantly changing IP addresses. We strongly recommend you don't try to block our web crawler by IP address, as you'll most likely spend several hours of futile effort and be in a very bad mood at the end of it.

Learn more

To learn more about SEO4Ajax, please check out the rest of the site. If you'd like to ask us any questions, don't hestitate to contact us.