Free User Agent Parser
Decode a user-agent into browser, OS & device.
What is the User Agent Parser?
Every request your browser makes carries a user-agent string — a dense, historical mess of tokens that names the browser, engine, operating system and device. Reading it by eye is a chore, and it's exactly the data behind your analytics device breakdowns and 'please upgrade your browser' messages.
This user-agent parser decodes any UA string into clean, labelled parts, and flags strings that look like bots.
Last updated: Aug 13, 2026
What does this tool do?
You paste a user-agent string (or use your own browser's) and the tool parses it.
It identifies the browser and version, the rendering engine, the operating system and the device type, and flags user agents that look like bots or automated clients.
Key features
Browser & version
Names the browser behind the string.
Engine
Blink, WebKit, Gecko or Trident.
OS detection
Windows, macOS, iOS, Android, Linux.
Device type
Desktop, mobile or tablet.
Bot flag
Highlights crawlers and headless clients.
Example
Common use cases
- Developers — Debug device-specific issues from logs.
- Analysts — Understand traffic by browser and device.
- QA engineers — Reproduce a user's environment.
- Support teams — Identify a user's browser to help them.
- Security teams — Spot suspicious or bot user agents.
- Marketers — Read device breakdowns in reports.
- Site owners — See what a crawler reports as its UA.
- Anyone curious — Decode their own user agent.
Benefits
- It turns a cryptic string into clear, labelled facts.
- It identifies browser, engine, OS and device at once.
- It flags bots and headless clients.
- It runs instantly in your browser.
Tips
- Don't rely on user agents for security — they're trivially spoofed.
- Use feature detection, not UA sniffing, to decide what code to run.
- Modern browsers freeze or reduce UA detail for privacy.
- Client Hints are the modern, structured alternative to the UA string.
- Bots often set a custom UA — check it before blocking.
- iPadOS may report a desktop Safari UA by default.
- Version numbers can be capped or frozen by the browser.
- Treat parsed results as a best guess, not proof.
Common mistakes to avoid
Trusting the UA for security
Fix: User agents are easily faked — never gate security decisions on them.
UA sniffing for features
Fix: Use feature detection so your code works regardless of the reported browser.
Assuming accuracy
Fix: Browsers freeze or spoof UA details; treat parsing as an estimate.
Blocking bots by UA alone
Fix: Legitimate crawlers set identifiable UAs; verify before blocking.
How it works
- 1
Paste a UA string
Or use your own browser's.
- 2
Parse
It breaks the string into components.
- 3
Review
See browser, engine, OS and device.
Frequently asked questions
The browser and version, rendering engine, operating system and device type from a user-agent string, and whether it looks like a bot.
It's a best guess — user-agent strings can be spoofed or frozen by modern browsers, so treat the result as an estimate.
The browser and version, rendering engine, operating system and device type, plus whether the string looks like a bot.
A line of text your browser sends with each request that describes itself — browser, engine, OS and sometimes device.
It's a best guess. UA strings can be spoofed and modern browsers freeze parts of them, so treat results as an estimate.
For historical compatibility reasons, most browsers include legacy tokens like Mozilla/5.0 and Safari regardless of the actual browser.
A modern, structured way for servers to request specific device info, designed to replace parsing the UA string.
No. Parsing happens entirely in your browser.
Conclusion
A user-agent parser makes a cryptic string instantly readable — browser, engine, OS and device at a glance. Pair it with the what-is-my-IP tool to see the full picture of what a site can tell about a visitor.