Vivaldi features the ability to "stack" and "tile" tabs, annotate web pages, and add notes to bookmarks.[18][19] Furthermore, users can place digital bookmarks on a "speed dial" page for quick access and harness "quick commands" to search bookmarks, browsing history, open tabs, and settings.[20] Vivaldi is built around and based on web technologies such as HTML5, Node.js, React.js, and numerous NPM modules.[21] As of Technical Preview 4, Vivaldi also supports numerous mouse gestures for actions like tab switching and keyboard activation.[17] Vivaldi can also be set to a "Chromeless UI", which gives users more screen real-estate and the ability to focus on a single page without distractions.[22]