How User Agent Checker Works

A User Agent Checker reads the User Agent information that your browser makes available to websites. As soon as you open the tool, it checks the raw User Agent string and tries to identify useful details such as your browser, browser version, operating system, device type, platform, and rendering engine.

Everything happens automatically inside your browser. You don’t need to install software, create an account, or enter any personal information. The tool simply reads the technical information that your browser already provides to websites.

Modern browsers may hide or reduce some details for privacy reasons. So, if you see “Not reported” for a device model, architecture, operating-system version, or another field, that doesn’t mean the tool is broken.

What Is a User Agent?

A User Agent is a piece of text that helps websites understand what kind of browser or software is making a request. Your browser normally sends this information when you visit a website.

A typical User Agent may contain clues about your browser, operating system, rendering engine, device type, and software version. Websites can use these details to improve compatibility or provide a layout that works better on your device.

The User Agent is not designed to contain your name, email address, password, or other personal account information.

What Does a User Agent Look Like?

A desktop browser User Agent might look similar to this:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36
(KHTML, like Gecko) Chrome/153.0.0.0 Safari/537.36

At first, this looks confusing. It contains several names, such as Mozilla, AppleWebKit, Chrome, Safari, and Gecko—even though the person may only be using Google Chrome.

That happens because User Agent strings have a long history of browser compatibility. Many old identifiers are still included so websites do not incorrectly reject modern browsers.

What Information Can a User Agent Checker Show?

A User Agent Checker can usually identify several useful details from your browser. These may include the browser name, browser version, operating system, device category, platform, rendering engine, browser language, and whether the User Agent looks like a known crawler or automated program.

Newer browsers may also provide User-Agent Client Hints, which can expose additional information such as architecture, bitness, platform version, browser brands, or device model when available.

The amount of information varies from browser to browser. Chrome, Edge, Firefox, Safari, Brave, Opera, and mobile browsers do not all expose exactly the same details.

What Browser Am I Using?

Your browser is the application you use to access websites. Common browsers include Google Chrome, Microsoft Edge, Mozilla Firefox, Safari, Brave, Opera, and Samsung Internet.

The User Agent Checker looks for browser-specific identifiers inside the User Agent string. For example, Chrome normally includes Chrome, Firefox includes Firefox, while Microsoft Edge commonly includes Edg.

Some browsers are based on Chromium and may therefore look very similar to Chrome. In those cases, additional browser information may be needed to correctly identify the browser.

What Is a Browser Version?

A browser version is the release number of the browser currently installed on your device. It may look something like 153.0.0.0, depending on the browser and how much version information it chooses to expose.

Knowing the browser version can be useful when troubleshooting websites. Certain web features may work in a newer browser but fail in an older version that does not support the same technology.

If a website suddenly stops working correctly, checking whether your browser is outdated is a sensible first step.

Why Does My User Agent Say Mozilla?

This is probably the most confusing part of a User Agent string. You may be using Chrome, Edge, or Safari and still see the User Agent beginning with:

Mozilla/5.0

That does not mean you are using Mozilla Firefox. The Mozilla/5.0 identifier is largely a historical compatibility convention that modern browsers continue to include.

Years ago, websites sometimes served different content based on browser names. Browsers began copying compatible identifiers so they would receive the same websites and features, and those old conventions still remain today.

Why Does Chrome User Agent Contain Safari?

A Chrome User Agent often contains both AppleWebKit and Safari, even though the user is clearly running Chrome.

Again, this is mainly about compatibility. Chrome originally used technology related to WebKit, and certain identifiers were retained so older websites would understand that the browser supported similar features.

You should therefore never identify a browser just by finding the word “Safari” somewhere in the User Agent. The complete string has to be interpreted in the correct order.

What Is a Rendering Engine?

A rendering engine is one of the main browser components responsible for turning website code into the page you see on the screen.

Common browser engines include Blink, WebKit, and Gecko. Chrome and Edge use Blink, Safari uses WebKit, while Firefox uses Gecko.

The engine matters because browsers can sometimes behave differently even when they support the same HTML, CSS, or JavaScript features.

What Operating System Can the User Agent Show?

A User Agent can often reveal the general operating system being used, such as Windows, Android, macOS, iOS, Linux, or ChromeOS.

In some cases, the User Agent also contains an operating-system version. However, exact OS detection has become less reliable because browsers are intentionally reducing detailed information.

For example, modern browsers may report the same traditional Windows identifier for different Windows releases. A responsible checker should therefore avoid pretending it knows an exact version when the browser has not provided enough information.

Can a User Agent Checker Detect Windows 11?

Not reliably from the traditional User Agent alone. Modern Chromium browsers often report a Windows identifier that can look the same on both Windows 10 and Windows 11.

Because of this, simply reading Windows NT 10.0 and automatically calling it Windows 10 can produce an incorrect result.

Newer browser features, such as User-Agent Client Hints, may provide additional platform-version information. Even then, detection should be treated carefully because availability depends on the browser.

Can a User Agent Show My Device Type?

Usually, yes—at least at a general level. The tool can often estimate whether you are using a mobile phone, tablet, or desktop/laptop.

Mobile User Agents often contain terms such as Mobile, Android, iPhone, or similar identifiers. Desktop browsers usually provide a different pattern.

However, this is still an estimate. Tablets using desktop mode, foldable devices, browser emulation, or modified User Agents can make device detection less certain.

Can It Detect My Exact Phone Model?

Sometimes—but not always. Certain Android browsers may expose a device model inside the User Agent or through User-Agent Client Hints.

Other browsers deliberately hide this information. Apple browsers, privacy-focused browsers, and newer browser versions may provide only broad device information.

If the tool says “Not reported,” it simply means your browser did not provide a dependable model value.

What Is User-Agent Client Hints?

User-Agent Client Hints are a newer browser technology designed to provide User Agent information in a more controlled way.

Instead of putting every possible detail into one long User Agent string, supported browsers can expose selected pieces of information separately. This may include browser brands, platform, mobile status, architecture, bitness, platform version, and device model.

The idea is to reduce unnecessary browser fingerprinting while still giving websites useful compatibility information when needed.

What Are Browser Brands?

Supported browsers may report a list of browser brands through User-Agent Client Hints. For example, a Chromium-based browser may provide information connected to Chromium and the actual browser brand.

You may also see unusual-looking brand names that seem unnecessary. Some browsers intentionally include “grease” values—basically unusual entries designed to prevent websites from depending too heavily on a fixed list of browser names.

So, seeing multiple brands does not mean multiple browsers are running at the same time.

What Does Architecture Mean?