Opera is a web browser for Windows, mac-OS, and Linux operating systems developed by Opera Software. It uses the Blink layout engine. An earlier version using the Presto layout engine is still available, and runs on FreeBSD systems.
Firefox is a Web browser that is smaller, faster, and in some ways more secure than the Mozilla browser from which much of its code was originally derived. Compared to Internet Explorer, the most popular Web browser, Firefox gives users a cleaner interface and faster download speeds.