Free Online User-Agent Parser — Identify Browser, OS & Device

Paste any User-Agent string to identify the browser, operating system, device type, and detect known bots. Your current browser UA is pre-filled for convenience.

User-Agent String

What Is a User-Agent String?

A User-Agent (UA) string is a text header that web browsers and HTTP clients send with every request to identify themselves to the server. It typically contains the browser name and version, the rendering engine, the operating system, and sometimes the device model.

Servers use this information for content negotiation (serving mobile vs. desktop layouts), analytics (tracking browser market share), and access control (blocking known bots or outdated clients). However, UA strings follow no strict standard — they are a jumble of tokens accumulated over decades of browser history, making them notoriously hard to parse manually.

This tool decodes that complexity into structured, human-readable output: browser, OS, device type, and bot detection — so you can quickly understand what a given UA string represents without memorizing arcane token patterns.

How to Use

Your current browser User-Agent is pre-filled automatically.
To analyze a different UA, paste it into the input field.
View the parsed results: browser name/version, OS name/version, and device type.
If the UA belongs to a known bot, a badge and documentation link are shown.
Click Copy JSON to export the structured result for use in code or reports.

When You Need This

Debugging responsive layout issues

When a user reports a rendering bug, parse their UA to identify the exact browser version, OS, and device type so you can reproduce the issue in the correct environment.

Analyzing access logs

Pull suspicious or unusual User-Agent strings from your server logs and parse them here to determine if they are legitimate browsers, known crawlers, or potential scrapers.

Verifying bot identity

When you see Googlebot or Bingbot in your logs, paste the full UA here to confirm it matches the official pattern and is not a spoofed bot.

QA and testing documentation

When writing test reports, parse the tester's UA to record the exact browser and OS combination that was tested, ensuring full traceability.

Tips

Don't rely on UA strings for security decisions

User-Agent strings can be easily spoofed. Use them for analytics and UX hints, but never as the sole factor for access control or feature gating.

Prefer feature detection over UA sniffing

Instead of checking the UA to decide whether a browser supports a feature, use feature detection (e.g., Modernizr or native APIs) for more reliable results.

Keep bot lists up to date

New crawlers appear regularly. If you maintain a server-side bot detection list, review it periodically and cross-reference with this tool's recognized bot database.

Log full UA strings for debugging

Always store the complete User-Agent in your logs. Truncated strings lose device or version info that may be critical for reproducing bugs.

Examples

Parse a Chrome desktop UA

Identifies Chrome version and Windows OS.

Input

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Output

Browser: Chrome 125.0
OS: Windows 10
Device: Desktop

Parse a mobile Safari UA

Identifies Safari on an iPhone.

Input

Mozilla/5.0 (iPhone; CPU iPhone OS 17_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.5 Mobile/15E148 Safari/604.1

Output

Browser: Safari 17.5
OS: iOS 17.5
Device: Mobile (iPhone)

Detect Googlebot

Recognizes the official Google crawler.

Input

Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)

Output

Bot: Googlebot 2.1
Type: Search Engine Crawler
Docs: google.com/bot.html

Limitations

UA string parsing is heuristic-based. New browsers or unusual UA strings may not be identified correctly.
Cannot detect UA spoofing — if a client lies about its browser, the parser has no way to know.
Does not parse Client Hints (Sec-CH-UA headers) which are replacing UA strings in modern Chrome.
Bot detection covers major search engines and known crawlers only. Custom or private bots may not be identified.

Features

Parse browser name and version (Chrome, Firefox, Safari, Edge, Opera, and more)
Identify operating system and version (Windows, macOS, Linux, iOS, Android)
Detect device type: desktop, mobile, or tablet
Recognize 13+ known bots and crawlers with documentation links
Auto-fills your current browser User-Agent on page load
Copy structured JSON result for use in code or reports
100% client-side — no data is uploaded

FAQ

Why are User-Agent strings so long and messy?

For historical reasons. Each new browser added tokens to appear compatible with older ones (e.g., "Mozilla/5.0" appears in nearly every UA). This accumulated legacy makes UA strings complex, but a parser extracts the meaningful parts for you.

Can this detect all bots?

It recognizes 13+ major bots (Googlebot, Bingbot, Slurp, DuckDuckBot, Baiduspider, etc.) by their official UA patterns. Custom or obscure bots that don't follow conventions may not be detected.

What happens if the UA string is spoofed?

The parser interprets the string as given. If someone spoofs their UA to look like Googlebot, the parser will report it as Googlebot. Verifying authenticity requires reverse DNS lookups on the request IP, which is a server-side operation.

Does this work with Client Hints?

This tool parses traditional User-Agent strings. Client Hints (Sec-CH-UA headers) are a newer, structured alternative. If you have Client Hints data, paste the individual header values and interpret them directly — no complex parsing needed.

Is my User-Agent sent anywhere?

No. Parsing runs entirely in your browser. The auto-filled UA is read from your browser's navigator.userAgent property locally.

Content last reviewed: June 2026

Your Privacy

All parsing happens entirely in your browser. No user-agent strings are uploaded to any server. Your browser information never leaves your device.

Tips & Related Workflows

Need to test a regex pattern for custom UA matching?Regex Tester.
Format the JSON output for documentation?JSON Formatter.
Compare two parsed results side by side?Diff Checker.