Presto was the browser engine of the Opera web browser from the release of Opera 7 on 28 January 2003, until the release of Opera 15 on 2 July 2013, at which time Opera switched to using the Blink engine that was originally created for Chromium. Presto was also used to power the Opera Mini and Opera Mobile browsers.
Presto is a dynamic engine. Web pages can be re-rendered completely or partially in response to DOM events. Its releases saw a number of bug fixes and optimizations to improve the speed of the ECMAScript (JavaScript) engine. It is proprietary and only available as a part of the Opera browsers.