User-Agent is a line that sends information to the site about the software used. Originally, websites used such data to identify the OS and browser version in order to correctly display embedded content. However, due to various reasons, early Web developers used different user agents for different browsers, and many users started faking their User-Agent value to view sites the way they wanted. Eventually developers started offering the option to change the User-Agent right in the settings.
The User-Agent allows to determine the operating system, device you use to access the site (smartphone, laptop, tablet etc.), and features supported by your browser like ActiveX.
If you need to change your User-Agent in Opera, Chrome, or Firefox, here is how you do it.
Please take note that the User-Agent is required to correctly display sites that lack responsive design, since different browsers use different styles and scripts to display the same content. Actual data about various values of these parameters are easily found on browscap.org and in the end of this post.
How to change User-Agent in Opera
In Opera, click on the address field and type the following address: opera:config#UserPrefs|CustomUser-Agent. In the field that appears with the title «Custom User-Agent», set the needed value of user-agent. Scroll the window down and save the changes made.
In more recent versions of Opera, for example 43.0, this feature is disabled. We recommend to install the extension User-Agent Switcher that allows to change the value in a handy menu.
How to change user agent in Google Chrome
Not all Chrome versions allow you to change your User-Agent easily. That said, the following guide works in all versions starting from 26. To change the User-Agent, click on the browser icon with the right mouse button, choose “Properties”, and in the new window, line “Start in”, type the key – -user-agent=””, and then in quotes the User-Agent you need.
Now click OK and launch Chrome. Alternatively, you can do the same by other methods, for example, by holding buttons Win and R, opening the “Run” window, and typing chrome – -user-agent=”needed value”.
To get to know the current value of this parameter, open the about local address:
How to change user agent in Mozilla Firefox
Like Chrome, not all versions of Firefox allow for easy changing of this parameter. The following guide works for versions starting from 34. In the address bar, type about:config, and in a page that opens, create the parameter general.useragent.override.
Choose the type of the parameter “String”, and in a new window type the user-agent value you need:
List of various user agents
— Mozilla/0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36
— Mozilla/5.0 (Windows NT 6.1; Win64; x86) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36
— Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C; .NET4.0E; Media Center PC 6.0; CMNTDFJS; F9J; InfoPath.3; rv:11.0) like Gecko
— Opera 12.17 (Win 8 x64): Opera/9.80 (Windows NT 6.2; WOW64) Presto/2.12.388 Version/12.17
— Internet Explorer 11 (Win 8.1 x64): Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; ASU2JS; rv:11.0) like Gecko