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User Agent Parser - Detect Browser, OS, Device & Bots

Your user agent is detected and fully parsed the moment you open this page. Paste any UA string to analyse it, compare two strings side by side, detect bots and crawlers, and get a segment-by-segment breakdown of what every part of a UA string actually means.

Always Free Auto-detected instantly Bot & crawler detection Runs in browser
Browser · Engine · OS · Device · Bot · Architecture
Your UA detected and parsed automatically on page load
Identifies 30+ bots and crawlers including Googlebot and Bingbot
Compare any two UA strings side by side to spot differences
Your current user agent - click to analyse
Paste any user agent string to parse it
Paste any user agent string above or click "Use my UA" to parse your current browser
UA Knowledge Quiz - test what you know
Question 1 of 8  ·  Score: 0

What makes it different

Other UA checkers show you the string.
This explains what every part of it means.

Segment breakdown, bot detection, compare mode, sample library, and dev code snippets - built for developers, not just browsers.

Segment breakdown

Every token in the UA string is colour-coded and explained - what each bracket means, why Chrome includes Mozilla/5.0, and what AppleWebKit is doing there.

understand, not just read

Bot detection

Automatically flags Googlebot, Bingbot, DuckDuckBot, and 30+ other crawlers - shows the crawler name, its purpose, and which company operates it.

spot crawlers instantly

Compare two UA strings

Paste two UA strings side by side and see exactly what differs - browser, version, OS, engine - highlighted in amber. Essential for cross-browser testing.

diff any two UAs

Sample UA library

20+ real user agent strings - Chrome, Firefox, Safari, Edge, iOS, Android, Googlebot, and legacy browsers - ready to test with one click.

test without a device

Dev code snippets

Ready-to-copy code for reading and overriding UA strings in Chrome DevTools, Firefox, Python, JavaScript, PHP, and cURL.

paste into your project

Auto-detected instantly

No input needed - your full UA string is parsed the moment you open the page. Browser, OS, device type, and engine shown before you scroll.

zero friction

Quick guide

Parse any user agent in seconds

1

View your UA instantly

Your browser's user agent is detected and parsed automatically - browser, OS, device type, and engine all shown on page load.

2

Paste any UA string

Test any user agent string - from the sample library, from server logs, or from a device you don't have access to.

3

Read the breakdown

See every segment colour-coded and explained. Use Compare mode to diff two UAs, and copy code snippets to override UAs in your dev tools.

What is a user agent string - and why is it so confusing?

A user agent (UA) string is a short piece of text your browser includes in every HTTP request it makes. It tells the web server what browser, version, operating system, and device type you're using. Servers use this information to decide what content to serve - a mobile layout, a different stylesheet, or even a completely different page.

Why Chrome says "Mozilla/5.0" when it's not Mozilla Firefox

This is the source of most UA confusion. A typical Chrome UA looks like: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36. Chrome is pretending to be Mozilla, AppleWebKit, and Safari simultaneously. This is called "UA spoofing for compatibility" - each browser included previous browsers' identifiers so websites that checked for specific UAs wouldn't block them. The result is a UA string that reads like an archaeological site of web history.

For developers: why UA detection is unreliable for feature detection. Because of decades of UA spoofing, using the UA string to detect browser capabilities is fragile. Modern best practice is to use feature detection (checking if navigator.geolocation exists, not whether the browser is Chrome) rather than UA sniffing. UA parsing is still genuinely useful for analytics, bot detection, and serving different layouts to mobile vs desktop.

How to read a user agent string

TokenWhat it means
Mozilla/5.0Legacy compatibility token - every modern browser includes this
(Windows NT 10.0; Win64; x64)OS: Windows 10/11, 64-bit architecture
AppleWebKit/537.36Rendering engine - Chrome uses Blink, a fork of WebKit
(KHTML, like Gecko)Another legacy compatibility token from Konqueror/Gecko era
Chrome/120.0.0.0The actual browser and version
Safari/537.36Legacy Safari compatibility token - Chrome includes this

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FAQ

User agent questions,
answered.

Ask a question
A user agent string is a text identifier your browser sends with every HTTP request. It tells the web server which browser, version, operating system, and device you are using so the server can serve the right content.
Your user agent is detected automatically when you visit this page. You can also find it in browser DevTools under Network → any request → Request Headers → User-Agent.
Paste any UA string into the input box above. The parser extracts browser name and version, rendering engine, OS and version, device type, CPU architecture, and whether the UA belongs to a bot or crawler.
Bot UA strings typically contain keywords like "bot", "spider", "crawler", or known names like "Googlebot" or "Bingbot". This tool flags them automatically and identifies the specific crawler and its operator.
Chrome includes Mozilla/5.0, AppleWebKit, and Safari tokens for historical compatibility - websites that checked for these identifiers would have blocked Chrome otherwise. The segment breakdown on this tool explains exactly what each part means.
Yes. In Chrome: DevTools → Network conditions → uncheck "Use browser default" under User agent. In Firefox: about:config → general.useragent.override. See the Dev Tools tab above for code snippets.