Opera is a web browser developed by opera software for windows, Mac OS and Linux operating systems. It uses a flicker layout engine. Earlier versions of the Presto layout engine are still available and can be run on FreeBSD systems. According to opera software, the browser had more than 350 million users worldwide in the fourth quarter of 2014. As of June 2015, the total number of opera mobile users reached 291 million. According to slashgeek, opera introduced features later adopted by other web browsers (including speed dial), pop-up blocking, browser sessions, private browsing and tabbed browsing

Opera started in 1994 as a research project for Telenor, Norway's largest telecommunications company. In 1995, it expanded to an independent company called opera software ASA. Opera first released version 2.0 in 1996 and only runs on Microsoft Windows. In order to take advantage of the emerging market of Internet connected handheld devices, the project of transplanting opera to mobile device platform was launched in 1998. Opera 4.0, released in 2000, includes a new cross platform kernel that facilitates the creation of versions. Opera is suitable for a variety of operating systems and platforms.