Request tool

User agent parser

Paste a browser, crawler, app, or bot user-agent string and see the parsed browser, engine, operating-system, mobile, and bot signals.

Browser: Unknown
Engine: AppleWebKit
Engine version: 537.36
Mobile: No
Bot: No
Mozilla: 5.0
Raw user agent: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)

Reference

Output fields

Browser: The recognizable browser or client family from the string, when one is detectable.
Engine and OS: Rendering engine and operating-system hints found in the user-agent value.
Mobile and bot: Parser hints based on known tokens, not proof of device type or automation.
Raw user agent: The original string is shown so parsed fields can be compared with the log value.

Overview

What this tool does

The user-agent parser turns a raw user-agent string into readable browser, engine, operating-system, mobile, and bot signals.

It helps with debugging browser compatibility, checking crawler traffic, and understanding request logs. User-agent strings can be spoofed, so treat the result as a hint. The user-agent guide explains the limits.

Examples

Example strings

Browser

Mozilla/5.0 ... Chrome/148.0.0.0 Safari/537.36 Shows browser, engine, operating system, and mobile hints when they are present. Parse browser example

Bot

Googlebot/2.1 Shows crawler-style detection when a bot token is recognizable. Parse bot example

Results

How to read results

Browser and engine values come from the recognizable tokens in the string. Mobile and bot values are hints from parser rules, not a security decision. The raw user-agent is included so you can compare the parsed fields with the original log value.

Boundaries

Limits

Clients control their user-agent strings. Browsers can freeze, shorten, or spoof values, and automated clients can pretend to be common browsers. Do not use user-agent parsing as the only fraud, rate-limit, or access-control signal.

For developers

Parse user agents in your code

Use a parser in your application to turn request headers or log entries into browser, OS, and device hints. These libraries have different rules, fields, and update schedules, so their results may differ from this tool. Test against strings from your own traffic and keep the parser's detection data up to date.

JavaScript / TypeScript

UAParser.js works in browsers and Node.js and includes TypeScript definitions. Install ua-parser-js with npm, then import UAParser and call UAParser(userAgent). The ESM / TypeScript quickstart shows the setup.

Version 2 is available under AGPL-3.0 or commercial licenses; check the project's license options before choosing an edition.

Python

ua-parser is useful for scripts and log processing. Install with pip install 'ua-parser[regex]', then use from ua_parser import parse and parse(user_agent) for browser, OS, and device results.

Go

mssola/useragent exposes browser, OS, mobile, and bot hints. Add github.com/mssola/useragent with go get, import it, and create a parser with useragent.New(userAgent). Read fields with methods such as Browser() and OS().

PHP

uap-php parses browser, OS, and device fields. Install with composer require ua-parser/uap-php, load Composer's autoloader, and create UAParser\Parser::create(). Call $parser->parse($userAgent) on that instance.

Java

YAUAA offers detailed analysis of user agents and Client Hints. Add the Maven dependency nl.basjes.parse.useragent:yauaa, create a UserAgentAnalyzer, and call parse(userAgent). Its integration guide covers instance reuse, logging setup, and limiting fields to reduce memory use.

C# / .NET

UAParser for .NET provides browser, OS, and device data. Install the UAParser NuGet package, create UAParser.Parser.GetDefault() once, and reuse it with Parse(userAgent) for each request.

A parsed user agent does not verify a visitor's identity or prove that a request is from a bot. Use browser feature detection for compatibility checks, and read the user-agent guide for spoofing and reduced browser strings.

Next steps

What is a user-agent? Understand browser, bot, platform, and spoofing signals. HTTP request headers explained See how user-agent data fits into the full request header set. View request headers Inspect the headers your current browser sends to ShowIP.