User-Agent String Parser
Paste a user-agent string to identify the browser, version, operating system, rendering engine, and device type — parsed instantly in your browser.
Parsed
- Browser
- Chrome 120.0.0.0
- Operating system
- Windows 10/11
- Rendering engine
- Blink
- Device type
- Desktop
User-agent parsing is heuristic. Strings can be spoofed or frozen (Chrome now reports a reduced UA), so treat the result as a best-effort guess, not proof of the real client.
About this tool
A user-agent string is the self-description a browser sends with every request, and decades of compatibility hacks have made it gloriously misleading: every browser starts with 'Mozilla/5.0', Chrome and Edge both claim to be 'Safari', and Edge claims to be Chrome. This parser untangles those tokens in the right priority order to report the actual browser and version, the operating system and version, the rendering engine (Blink, Gecko, WebKit, Trident), and whether the device looks like a desktop, tablet, or phone. Because the format is unstandardized and increasingly 'frozen' or reduced by browsers for privacy, the result is a best-effort heuristic rather than a guarantee — user-agent strings can be trivially spoofed and should never be used for security decisions. A button lets you parse your own browser's string. All parsing happens locally.
How to use it
- Paste a user-agent string, or click 'Use my browser's' to load your own.
- Read the detected browser, OS, engine, and device type.
- Remember the result is a heuristic — UA strings can be spoofed or reduced.
- Copy the parsed summary if you need it elsewhere.
Frequently asked questions
- Why does every user-agent contain "Mozilla/5.0"?
- It is a historical compatibility token. In the 1990s servers sent richer pages to "Mozilla"-capable browsers, so every browser started claiming to be Mozilla to receive them. The token is now meaningless but universal, which is why parsers ignore it.
- Why is detection only "best-effort"?
- User-agent strings are unstandardized and full of legacy and decoy tokens (Chrome includes "Safari", Edge includes "Chrome"). Detection relies on checking the most specific markers first. It is accurate for mainstream browsers but can misfire on obscure or deliberately altered strings.
- Can a user-agent string be faked?
- Yes, trivially — any client can send any string, and browser extensions and developer tools let users override it. Never use the user-agent for authentication, licensing, or security gating; use it only for analytics and non-critical content adaptation.
- What is "user-agent reduction"?
- For privacy, Chrome and other browsers now send a reduced UA that hides the precise OS and full browser version, exposing detail through the newer Client Hints API instead. So a modern Chrome string may report less than older ones, and that is expected.
- What does the rendering engine tell me?
- The engine — Blink (Chrome, Edge, Opera), Gecko (Firefox), WebKit (Safari), or Trident (old IE) — determines how pages are actually laid out and which CSS/JS features are supported. It is often more useful for compatibility decisions than the browser brand.
- Is the string I paste sent anywhere?
- No. Parsing is pure in-browser pattern matching with no network calls, so any string you test stays on your device.