How to parse a user agent
- Your own browser's User-Agent is filled in automatically. To check another one, paste it from a server log, analytics export or bug report.
- The browser and version, rendering engine, operating system and version, device type (desktop, mobile, tablet, TV or bot) and, where available, the phone model are shown instantly.
- Copy the result as JSON for a ticket or test fixture.
What is a User-Agent string?
Every HTTP request carries a User-Agent header describing the software that made it. For historical reasons these strings are confusing: almost every browser starts with Mozilla/5.0, Chrome claims to be Safari, and Edge claims to be Chrome. A parser has to check tokens in the right order, for example looking for Edg/ before Chrome/, to identify the real browser.
Developers parse user agents to debug browser-specific bugs, to understand traffic in logs, and to spot crawlers such as Googlebot, Bingbot, GPTBot and ClaudeBot, social preview bots, or scripts using curl and Python. Remember that a User-Agent is self-reported and can be faked, so never rely on it for security.
Frozen user agents
To reduce fingerprinting, Chrome, Edge and other browsers now "freeze" parts of the string: Windows 11 still reports Windows NT 10.0, macOS versions are capped at 10.15.7, and Android hides the device model in many cases. Accurate details are available to sites through User-Agent Client Hints instead. This parser therefore shows "10 or 11" for modern Windows.
Parsing happens in your browser; nothing you paste is sent anywhere.
How do I find my user agent?
It is shown above as soon as the page loads. In code, read navigator.userAgent in the browser or the User-Agent request header on the server.
Can I tell Windows 10 and 11 apart?
Not from the User-Agent, which reports Windows NT 10.0 for both. Use the Sec-CH-UA-Platform-Version client hint: values of 13 or higher mean Windows 11.
How can I detect bots reliably?
Check the User-Agent first, then verify important crawlers by reverse DNS lookup, as Google and Bing recommend, because bad bots often pretend to be Googlebot.