Network/HTTP
User-Agent Parser
Break a User-Agent string down into browser, engine, operating system, and device type.
The User-Agent string a browser sends with every request looks like a chaotic mix of names and versions, largely because of browsers' historical habit of impersonating each other (nearly every modern browser's string still contains "Mozilla/5.0"). This tool breaks it down into browser, engine, OS, and device type.
How to use it
- Paste a User-Agent string (from your own dev tools console or from server logs) and it's parsed instantly.
- The result shows the browser name and version, the rendering engine, the operating system, and the device type (desktop, mobile, tablet, bot).
- Handy for recognizing bot and crawler strings (Googlebot, Bingbot, etc.), which also send a User-Agent.
Common uses
- Debugging a bug that only shows up in a specific browser or OS — quickly figuring out what the user was actually on from a log entry.
- Analyzing server logs for the share of mobile traffic or outdated browsers among visitors.
- Checking whether a request genuinely came from a legitimate search bot, rather than someone spoofing its User-Agent.
Things to keep in mind
A User-Agent is entirely controlled by the client and easy to spoof — don't rely on it for security decisions.
Under the User-Agent Reduction effort, modern browsers increasingly freeze or simplify OS and device details for privacy — detection accuracy is gradually declining.
Article about this tool: User-Agent: why this string is such a mess
Frequently asked questions
Why do so many User-Agent strings mention "Mozilla" even in Chrome or Safari?
This is a historical artifact — browsers kept adding "Mozilla/5.0" to their User-Agent strings for compatibility with old server checks written for early Netscape Navigator, and the convention never went away.
How reliable is User-Agent parsing for detecting the actual browser and OS?
Reasonably reliable for common cases, but User-Agent strings can be spoofed, and some browsers now freeze or simplify parts of the string for privacy, so detection isn't guaranteed to be exact.
Is the User-Agent string I paste here sent anywhere?
No. Parsing happens entirely in your browser — nothing is uploaded to a server.
What are User-Agent Client Hints?
A modern alternative to the single User-Agent string — a set of separate headers (Sec-CH-UA, Sec-CH-UA-Platform, etc.) that a server must explicitly request and receives in a structured format, instead of parsing one cluttered string.
Why do some browsers hide the exact OS version or device model in the User-Agent?
It's part of the "User-Agent Reduction" effort for privacy — detailed OS version or device model info can be used to uniquely fingerprint a user, so browsers are gradually simplifying or freezing those parts of the string.