The Serpstat Website SEO Checker is a Chrome extension that allows you to instantly check your website's SEO, analyze competitors, and access powerful search analytics. With this extension, you can easily find the key metrics of any site or page, such as visibility, traffic, number of keywords, and top competitors in the region. It offers three sections for analysis: on-page SEO parameters, page analysis, and domain analysis. Some features can be accessed without signing up, while others require a token for API access. This extension is designed to make competitor analysis and keyword research easier and more efficient.