User Agent Checker

What Is a User-Agent String?

A User-Agent string is a line of text that a web browser sends to a website with each request. It describes the software making the request, usually the browser, its version, the operating system and sometimes the type of device. Websites and servers can use it to decide how to deliver a page, for example whether to send a layout built for small screens.

The name comes from the idea that the browser acts as the user's agent on the web. The same kind of string is also sent by apps, search engine crawlers and command-line tools.

What Does a User-Agent Look Like?

Most browser strings follow a similar pattern. Here is the example for Chrome on Windows, which you can load with the example button above:

• Mozilla/5.0 is a historical token that nearly every browser still sends for compatibility. It does not mean the browser is Mozilla or Firefox.
• (Windows NT 10.0; Win64; x64) describes the operating system and processor type.
• AppleWebKit/537.36 (KHTML, like Gecko) refers to rendering-engine history. Many browsers include it for compatibility.
• Chrome/120.0.0.0 names the browser and its version.
• Safari/537.36 is another compatibility token that Chrome and many other browsers include.

Because so many browsers copy each other's tokens, reading a string correctly means checking the most specific names first. This tool does that, and the "How this string was read" list under each result shows the pieces it found.

How This User Agent Checker Works

The page reads your browser's own User-Agent string and shows it for you to copy. It then reads known tokens in that string, using a small set of built-in rules, to infer the browser, its version, the operating system and the device type. The same rules are used when you paste a different string.

When the string does not clearly support an answer, the tool says so with a tag such as Unknown, Uncertain or Conflicting signals instead of guessing. No result is verified, because a User-Agent string is only a claim made by the software that sent it.

Browser-Reported vs Inferred Information

This page keeps two kinds of information apart. Reported values are given by your browser directly, such as your language setting, screen size and time zone. Inferred values are worked out by reading the User-Agent string, such as the browser name or the operating system.

Why User-Agent Strings Can Be Reduced, Changed or Misleading

• Reduction: Chromium-based browsers such as Chrome and Edge now show fewer details on purpose. The minor version numbers appear as zeros, so a string like Chrome/120.0.0.0 only tells you the major version. Chrome on Android can show a fixed Android version, and browsers on macOS commonly report a frozen macOS version. Windows 11 still reports itself as Windows NT 10.0.
• Modification: Browser extensions, developer tools and privacy-focused browsers can change what is sent. Developer tools can emulate other devices.
• Desktop-site mode: A phone asking for the desktop version of a site can send a desktop-style string.
• Shared tokens: Different browsers that use the same engine can send the same tokens. For example, several Chromium-based browsers all say Chrome, so a string alone often cannot name the exact browser.
• Bots and tools: Crawlers and scripts can send any string they like, including one that copies a real browser.

For these reasons, treat a User-Agent string as a claim, not proof. Detected and Likely results are useful clues, but none of them is verified.

What Are User-Agent Client Hints?

User-Agent Client Hints are a newer browser feature, currently available in Chromium-based browsers, that gives sites structured information in place of the long string. By default only low-detail values, such as the browser brands, whether the browser is mobile and the platform name, are available. Sites can ask for more detail, but this tool deliberately does not. It only shows the low-detail values when your browser offers them, and labels them as browser-reported.

What Do Unknown or Conflicting Results Mean?

Unknown means the string has no token that the tool recognises for that item. This is common for new browsers, unusual devices, apps and custom strings. Conflicting signals means the string contains signs of more than one operating system, which can happen when a string has been edited or combined. Uncertain marks cases such as an iPad that reports itself as a Mac, where the string alone cannot settle the question. In all of these cases the tool leaves the answer open instead of choosing one.

Privacy: What This Tool Does and Does Not Do

This tool works entirely in your browser. It does not send your User-Agent, or any string you paste, to another service, and it does not use cookies or save anything in your browser. It does not request detailed Client Hints and does not use fingerprinting techniques. As with any website, the server that delivers this page receives your browser's normal request information, including the User-Agent header, when the page is loaded. This tool adds nothing to that. For more on how this website handles information, read the Privacy Policy.

Related Tools and Guides

A User-Agent describes your software. Your IP address describes your network connection, and the two are separate. To see your public IP address, ISP and approximate location, use the WhatIsMyIP homepage, or read what an IP address is and how IP location works. A VPN usually changes the IP address that websites see, not your User-Agent. You can read more in VPN detection and proxy detection. To look up a domain's records, try the DNS Lookup tool, and learn more about the site on the About page.

Frequently Asked Questions