What Is My User Agent?
Use the user agent lookup tool above to see what your user agent, or UA, presents as to the websites you visit within your browsing session. Once you have the information from the user agent checker, learn how to change your UA in the sections below.
What is a user agent?
A user agent, or UA, is a string of information that identifies a user’s browser and operating system. When you visit a website, your Internet browser sends information to the web page about your web browser, operating system, device, screen resolution, and more. When the browser communicates with websites in this way, on behalf of the individual, the browser acts as a UA. This is the information you see in the user agent lookup results.
The purpose of UAs is to allow servers and network peers, like websites, to identify information about the user. To clarify, this includes application, operating system, and browser identification, along with other technical details. This allows websites to optimize browsing experiences for people across all browsers and operating systems.
Websites that can detect UA information are capable of redirecting mobile customers to the mobile version of the website. This enhances the customers’ experience and makes them more likely to return. Not all sites have UA detection in place, however; in some cases, the lack of UA detection is what makes a website look bad on mobile.
User agent examples
In user agent strings or user agent headers, the most important information is provided first. A default UA string looks like this:
Mozilla/[version] ([system and browser information]) [platform] ([platform details]) [extensions]
That displays the browser version, the platform you’re accessing the website on, and more data. It acts as a type of digital log. It notes the information where your search began and delivering it to the site.
With that default browser identification string in mind, a person on a Windows 10 computer using Google Chrome has an agent that looks similar to this:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36
Can I change my user agent?
Yes, it’s possible to change your UA. Web developers often use user agent switchers or user agent managers. It allows them to see how their websites look and perform with different browsers or on different devices.
This is often referred to as user agent spoofing. If you check an agent in the test and aren't happy with it, you can change it.
It’s not a dangerous activity, and it’s not against the law by any means; users are welcome to do it. Using UA switching tools and managers quickly and easily replaces your browser UA string with a custom UA string. However, UA spoofing can also be done by bad actors looking to disguise their web traffic to avoid discovery. If you choose to alter your UA, make sure you are doing so for legitimate reasons.
How to change your user agent
Because each browser is unique, each has a unique code that appears in the browser as the default user agent string. Knowing how to change the UA in Chrome is different than knowing how to change the UA in Firefox.
For Microsoft Edge, Safari, and Google Chrome user agent changes, you can use the browser-supported built-in tools. However, to change the Firefox user agent, you’ll have to use an add-on called User-Agent Switcher.
With any of these methods, you will be able to change your UA to mask yourself as using a different browser, browser version, operating system, or screen resolution. Again, this is very useful when testing how websites, URLs, or domains will perform in various situations.
If you’re not a web developer and simply want more privacy when browsing the Internet, there is another option. You can use a random user-agent, which replaces your browser user agent string with a different, random UA string after a specified period of time.
However, if privacy is your goal, consider using a proxy or VPN. Both proxies and VPNs mask your real IP address, which helps achieve the same result as a random UA. You can view your real IP address on the What Is My IP home site.
Frequently asked questions
What is the use of a user agent?
The purpose of a UA is to identify your device and allow other devices to identify it when sending or retrieving web content. It identifies your browser and operating system, facilitating proper communication and functioning between your device and sites you visit.
How do I find out my user agent?
To find out your UA, use the UA check tool above. The tool returns your agent string, which will help you change it if you want to.
Can the UA be manipulated?
Yes, you can change or manipulate your UA for testing purposes. Follow the steps above for changing your UA in order to test content on your browsers or mobile devices.
Does JavaScript show a user agent header?
If you have JavaScript, then yes, it's possible to get your UA or HTTP agent header. However, it's easier to use the tool above, especially for those unfamiliar with JavaScript.