What's the Latest Version of Firefox User Agents?

What is the User Agent Mozilla?

A User Agent is a string of text sent by a browser to a website, identifying the browser and its underlying platform. For example, the User Agent Mozilla is a specific identifier used by browsers that are based on Mozilla technologies, primarily Mozilla Firefox, and it provides important details about the browser, operating system, and device for compatibility and rendering purposes.

Mozilla User Agent Format

An example of a Mozilla User Agent string would look like this:

The User Agent string "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0" contains the following components:

• Mozilla/5.0: A legacy identifier used for compatibility with websites expecting Mozilla-based browsers.
• (Windows NT 10.0; Win64; x64): Specifies the operating system (Windows 10/11, 64-bit version).
• rv:138.0: Indicates the Firefox browser version (138.0).
• Gecko/20100101: Shows the rendering engine (Gecko) and its version.
• Firefox/138.0: Specifies the browser (Mozilla Firefox) and its version number (138.0).

Why Does Mozilla User Agent Include Legacy Tokens?

The inclusion of Mozilla/5.0 in modern browsers is mostly for backward compatibility. When the User Agent string was first developed, browsers like Netscape Navigator used "Mozilla" as part of their identifier. Over time, other browsers (including Firefox) adopted this convention for compatibility with older websites that might expect it.

How to Modify the Mozilla User Agent

Modifying the User Agent string can be useful in several scenarios, such as testing how a website behaves on different browsers or devices. Here's how you can modify it in Mozilla Firefox:

Using Developer Tools:

• Press F12 to open the Developer Tools.
• Go to the Network Conditions tab.
• Uncheck "Use browser default" under the "User Agent" section.
• You can then enter your custom User Agent string manually.

Using Extensions:

There are several browser extensions available (such as User-Agent Switcher) that allow you to change the User Agent string persistently, providing a more user-friendly way to test different user environments.

How to Check the Mozilla User Agent

Via Firefox Browser:

• Open Firefox and go to about:support in the address bar.
• Look under the User Agent section to view your current string.

Using JavaScript:

• Open Developer Tools (F12) in Firefox.
• Go to the Console tab and type the following:

navigator.userAgent;

Using Online Tools:

You can also visit websites like What is My User Agent to instantly see the User Agent string for your Mozilla Firefox browser.

What is my User Agent?