A viewport meta tag is HTML (HyperText Markup Language) code that tells browsers how to control viewport dimensions and scaling. Adding meta viewport tags will make your page more responsive. Image Source: GoogleMost content management systems (CMS) will automatically set optimal viewport meta tags for your website. A viewport meta tag, like other meta tags, is HTML that goes into the page’s <head>. Viewport meta tags are a small but vital part of optimizing your site for user experience, accessibility, and search performance.