User-Agent Parser

Parse and decode User-Agent strings.

Developer

About User-Agent Parser

A User-Agent string is a text identifier sent by web browsers, apps, and bots with every HTTP request. It typically contains the browser name and version, the operating system, the rendering engine, and sometimes the device type. For example, a Chrome browser on Windows might send: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36.

This tool parses User-Agent strings using the widely-used ua-parser-js library, extracting structured information about the browser, OS, and device. This is useful for web developers debugging browser-specific issues, support teams identifying customer environments, and analysts understanding traffic patterns. Since parsing runs entirely in your browser using JavaScript, no data is transmitted to any server.

How to Use User-Agent Parser

  1. Paste a User-Agent string into the input field, or click Use my browser's User-Agent to auto-detect your current browser.
  2. The parsed result instantly shows the detected browser name and version, operating system, and device type.
  3. Use this information for debugging, support tickets, or documentation.

Key Features

  • Browser detection — Identifies browser name, version, and rendering engine
  • OS detection — Detects operating system name and version
  • Device identification — Reports device type (desktop, mobile, tablet)
  • Auto-detect — One click to parse your own browser's User-Agent
  • Powered by ua-parser-js — Uses a widely-used, well-maintained parsing library
  • Client-side privacy — No server communication; your data stays local

When to Use This Tool

  • Debugging browser-specific rendering or JavaScript compatibility issues
  • Identifying the browser and OS environment from customer support tickets
  • Analyzing User-Agent strings from web server logs
  • Verifying that search engine bots and crawlers are properly identified
  • Understanding what information your browser reveals about your device

Technical Details

The parser uses the ua-parser-js library, which applies a comprehensive set of regular expressions to extract structured data from User-Agent strings. It identifies hundreds of browsers (Chrome, Firefox, Safari, Edge, Opera, and many more), operating systems (Windows, macOS, Linux, Android, iOS), and device types (desktop, mobile, tablet). When you click "Use my browser's User-Agent", the tool reads navigator.userAgent from your browser — this value is not sent anywhere. Note that different parsing libraries may produce slightly different results due to variations in their regex patterns and databases.

Conclusion

User-Agent Parser is a practical tool for developers, support teams, and analysts who need to decode User-Agent strings quickly and privately. With comprehensive browser, OS, and device detection powered by ua-parser-js, it turns cryptic User-Agent headers into actionable information — all within your browser. For related web tools, try the HTTP Headers Parser.

Frequently Asked Questions

What is a User-Agent string?
A User-Agent is a text identifier sent by browsers and apps with HTTP requests. It contains the browser name, version, operating system, and sometimes device information. Servers use it for analytics, compatibility, and content negotiation.
Is my User-Agent sent to a server?
No. When you click "Use my browser", we read navigator.userAgent locally in your browser. When you paste a string, we parse it locally with JavaScript. Nothing is sent to our servers.
Why might parsing results differ from other tools?
Different parsing libraries use different regex patterns and databases. We use ua-parser-js, which is widely used and actively maintained, but minor differences with other parsers can occur for uncommon or custom User-Agent strings.
Can it detect bots and crawlers?
Yes. The ua-parser-js library can identify many common bots and crawlers (Googlebot, Bingbot, etc.) based on their User-Agent strings, though custom or lesser-known bots may not be recognized.