Ahrefs uses its own SEO crawlers to scan the web.

It claims to have the biggest commercially available backlink database and one of the biggest keyword databases on the market.

While no SEO tool has a complete view of the web, Ahrefs is probably as close as one can get.

Over the years, Ahrefs kept adding more and more SEO features, to the point where it can be a little overwhelming for those just starting out with search optimization.

The tool is a much better fit for intermediate and advanced users, like SEO freelancers and SEO agencies.

Free Trial

Ahrefs does not offer a free SEO plan, but it offers a trial plan so cheap that it’s almost free.