Opera is a web browser developed by Opera Software. The latest versions of Opera use the Blink layout engine. Earlier versions used Opera Software’s proprietary Presto layout engine and had additional Internet suite features such as sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent, and reading web feeds. Opera is offered free of charge for personal computers and mobile devices. According to Opera Software, the browser has over 300 million monthly users worldwide.

Opera is the third most popular mobile web browser as of November 2013. Opera Mini has been chosen as the default integrated web browser in several mobile handsets by their respective manufacturers.

Features include tabbed browsing, page zooming, mouse gestures, and an integrated download manager. Its security features include built-in phishing and malware protection and the ability to delete private data such as HTTP cookies. Opera has been noted for originating many features later adopted by other web browsers, a prominent example being Speed Dial.

Opera runs on a variety of personal computer operating systems, including Microsoft Windows, OS X, Linux, and FreeBSD. Opera editions are available for devices running the Android, iOS, Symbian, Maemo, Bada, BlackBerry and Windows Mobile operating systems, and Java ME.