A user agent is a computer program representing a person, for example, a browser in a Web context.
Besides a browser, a user agent could be a bot scraping webpages, a download manager, or another app accessing the Web. Along with each request they make to the server, browsers include a self-identifying User-AgentHTTP header called a user agent (UA) string. This string often identifies the browser, its version number, and its host operating system.
Firefox User Agent Strings Firefox Click on any string to get more details Firefox 77.0. Mozilla/5.0 (Windows NT 6.1; WOW64; rv:77.0) Gecko/20190101 Firefox/77.0. Jul 03, 2017 Click Develop User Agent and select the user agent you want to use in the list. If the user agent you want to use isn’t shown here, select “Other” and you can provide a custom user agent. You can find extensive lists of user agents on various websites, such as this one. This option only applies to the current tab. You can perform detailed user agent searches, including refining by software/browser name and version, operating system name and version, software type (browser, bot, app etc), hardware type and so on. You can easily find groups of user agents that match your search criteria. Use the API to decode user agents. The browser has a basic style sheet that gives a default style to any document. These style sheets are named user-agent stylesheets. Some browsers use actual style sheets for this purpose, while others simulate them in code, but the end result is the same. Some browsers let users modify the user-agent stylesheet. A user agent tells websites what type of browser and operating system you're using. This information helps the web server deliver content that's compatible with your browser. If websites tell you that your browser is outdated or incompatible even though Firefox is.
Spam bots, download managers, and some browsers often send a fake UA string to announce themselves as a different client. This is known as user agent spoofing.
The user agent string can be accessed with JavaScript on the client side using the NavigatorID.userAgent property.
A typical user agent string looks like this: 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0'.
Learn more
General knowledge
- User agent on Wikipedia
Technical reference
Hola Free
- RFC 2616: 14.43: The
User-Agentheader
User Agent Mozilla/4.0
| User agent | Browser Version | OS | Hardware Type |
|---|---|---|---|
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:65.0) Gecko/20100101 Firefox/65.0 | 65 | Mac | Computer |
| Mozilla/5.0 (Windows NT 6.2; rv:60.0) Gecko/20100101 Firefox/60.0 | 60 | Windows | Computer |
| Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20100101 Firefox/25.0 | 25 | Windows | Computer |
| Mozilla/5.0 (Windows NT 5.1; rv:52.9) Gecko/20100101 Gecko/3.5 Firefox/52.9 K-Meleon/76.4.3 | 52 | Windows | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:75.0) Gecko/20100101 Firefox/75.0 | 75 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:71.0) Gecko/20100101 Firefox/71.0 | 71 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:79.0) Gecko/20100101 Firefox/79.0 | 79 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:83.0) Gecko/20100101 Firefox/83.0 | 83 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:74.0) Gecko/20100101 Firefox/74.0 | 74 | Mac | Computer |
| Mozilla/5.0 (X11; Linux x86_64:88.0) Gecko/20100101 Firefox/88.0 | 88 | GNU/Linux | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:73.0) Gecko/20100101 Firefox/73.0 | 73 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:49.0) Gecko/20100101 Firefox/49.0 | 49 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:59.0) Gecko/20100101 Firefox/59.0 | 59 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:52.0) Gecko/20100101 Firefox/52.0 | 52 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:53.0) Gecko/20100101 Firefox/53.0 | 53 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:48.0) Gecko/20100101 Firefox/48.0 | 48 | Mac | Computer |
| Mozilla/5.0 (X11; U; CrOS i686 9.10.0; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Gecko/20100101 Firefox/29.0 | 29 | unknown | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 11.5; rv:83.14) Gecko/20100101 Firefox/83.14 | 83 | Mac | Computer |
| Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:80.0) Gecko/20100101 Firefox/80.0 | 80 | Mac | Computer |
| Mozilla/5.0 (Windows NT 10.0; rv:83.0) Gecko/20100101 Firefox/83.0 | 83 | Windows | Computer |