SimilarWeb is a website that provides web analytics services for businesses. The company offers its customers information on their clients' and competitors' website traffic volumes, referral sources which include keyword analysis and demographics, and website "stickiness" (e.g., time on site, page views, bounce rate), as well as other features.

It extrapolates data from a panel of web users who allow the monitoring of their internet activity, combined with direct observations for a subset of internet properties, such as websites' own traffic statistics. In 2019, it claimed to have the world's largest panel, with hundreds of millions users