Bootlint is a tool that checks for several common HTML mistakes in webpages that are using Bootstrap in a fairly "vanilla" way. Vanilla Bootstrap's components/widgets require their parts of the DOM to conform to certain structures. Bootlint checks that instances of Bootstrap components have correctly-structured HTML. Optimal usage of Bootstrap also requires that your pages include certain <meta> tags, an HTML5 doctype declaration, etc.; Bootlint checks that these are present. Bootlint assumes that your webpage is already valid HTML5. If you need to check HTML5 validity, we recommend tools like vnu.jar, grunt-html, or grunt-html-validation.