Ahrefs is an online marketing platform for search engine optimization (SEO), the work of making a website appear higher in search results, made by Ahrefs Pte. Ltd. Its data comes from Ahrefs' own index of the web, collected by a crawler (a program that downloads web pages and follows their links) that Ahrefs calls the second-most active in the world.
Keywords Explorer shows what people search for in Google: for each keyword it gives the monthly search volume, a Keyword Difficulty score based on the links that point to the top-ranking pages, the traffic potential of the first result, and the parent topic; it generates thousands of related keyword ideas and groups them. Its index holds 28.7 billion keywords in 217 locations. Site Explorer studies any website, including competitors' sites, and backlink tools list the links that point to a site from other sites. Other tools track rankings, audit a site for technical problems, and measure how often a brand appears in answers from AI chatbots.
Ahrefs is a hosted subscription service, billed monthly or yearly. A free plan, Ahrefs Free, covers data about the user's own site.