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User-Agent Parser

User-Agent Parser: Guide to Browser String Analysis

7 min read

2026-02-03

How the User-Agent parser works, what information can be extracted, and why web developers need it.

What Is a User-Agent?

A User-Agent is a string in the HTTP header that the browser sends to the server with every request. It contains information about the browser, operating system, and device.

User-Agent String Structure

A typical string contains:

•

Browser name and version

•

Rendering engine (Blink, Gecko, WebKit)

•

Operating system and its version

•

Device type (desktop, mobile, tablet)

What Can Be Detected

ParameterExample
BrowserChrome 120, Firefox 121, Safari 17
OSWindows 11, macOS 14, Android 14
DeviceDesktop, iPhone, Samsung Galaxy
EngineBlink, Gecko, WebKit
BotGooglebot, Bingbot, YandexBot

How to Use the Parser

1.

Copy the User-Agent string from the browser or logs

2.

Paste it into the analysis field

3.

Get structured information about the device and browser

Where to Find the User-Agent

Limitations

The User-Agent can be spoofed by the user or an extension. Many modern browsers also standardize the string for privacy protection.

Analyze a string with the User-Agent Parser.

See also: MAC Address Lookup, Port List

Try User-Agent Parser

Parse and analyze User-Agent strings

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