What Does Your User Agent Say About You?


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-Agent HTTP header called a user agent (UA) string. This string often identifies the browser, its version number, and its host operating system.

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 navigator.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".


User Agent String

Browser Data

Sample User Agent String

Brent Mccoy
• Tuesday, 05 July, 2022
• 8 min read

Platform identifiers change based on the operating system being used, and version numbers also increment as time passes. Mapping UA string tokens to a more human-readable browser name for use in code is a common pattern on the web today.

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When mapping the new Edge token to a browser name, Microsoft recommends using a different name than the one developer used for the legacy version of Microsoft Edge to avoid accidentally applying any legacy workarounds that are not applicable to Chromium-based browsers. When Microsoft is notified about these types of issues, website owners are contacted and informed about the updated UA.

While all phones come with pre-installed browsers, both Google Play and Apple App Store offer a number of alternative browsers, some focusing on speed and lightness, others on saving bandwidth and blocking ads, and an ever-increasing amount claiming to increase privacy and reduce a users' mobile digital footprint. Feel free to browse the stats for your local market using our Data Explorer tool.

There are more than 100 predefined user agent strings available to choose in the Add-on options page. This list covers all modern browsers including Google Chrome, Mozilla Firefox, Opera, Safari, Marathon, as well as Mozilla Thunderbird browser and many more.

Also, all the user agents are provided for both desktop and mobile platforms. Each UA can also be modified from add-ons options page to match your specific need.

Custom Sergeant String (abbreviated as Cuts) is a browser add-on (extension) that enables you to quickly change the user agent (UA) of your browser to your desired value. Once you install the add-on, please go to the options page to start working with this extension.

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How do I work with Custom Sergeant String add-on? In order to find an user agent, as mentioned above, you can use the predefined UA table and choose a string from there.

There are more than 100 UAS available in the table for almost all modern browsers and ranging from desktop to mobile platforms. There are plenty of websites to offer free user agent string lists.

Two methods for reading and extracting information from the useragentstring include brute force and pattern recognition: Though it offers a relatively simple implementation, the brute force approach can be difficult to maintain and becomes increasingly inefficient as comparison data sets grow larger.

Thanks to RFC 2616 and preceding RFCs, and de facto standards for formatting user agent strings, another method known as pattern recognition is possible. Using pattern recognition the user agent string is broken into its component pieces and heuristics applied to gather information.

Though more complex to implement than the brute force approach, pattern recognition does not suffer from the same problems in efficiency and maintainability in the long-run. Due to its drawbacks in the application of extracting data form user agent strings, the brute force approach will not be discussed further in this article.

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User agent is an HTTP request header string identifying browser, application, operating system which connects to the server. Not only browsers have user agent but also bots, search engines crawlers such as Google bot, Google AdSense etc.

If you have Django.core.context_processors.request enabled, user _ agent will also be available in template through request : Django- user _agents comes with get_ user _ agent which takes a single request argument and returns a Sergeant instance.

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