Why does every browser claim to be Mozilla?

A compatibility check from the 1990s tested for it before serving modern content. Browsers added the token to pass, and it has never been safe for any of them to remove. The same history explains why Chrome claims Safari and Edge claims both.

Can I trust that a request really came from Googlebot?

No. Anyone can send that string. Verifying it means a reverse DNS lookup on the connecting IP address followed by a forward lookup on the result — Google documents the procedure, and it is the only reliable check.

Why does the version look truncated?

Because it is. Chrome freezes the minor version components and reports the major version only, and Safari reports a fixed WebKit build number, both to reduce fingerprinting. There is no more detail available to extract.

Should I use this to decide what to serve?

No. Feature-detect instead, or read the Sec-CH-UA client hints. Branching on a user-agent breaks silently every time a browser changes its string, and browsers change their strings specifically to break that pattern.

User Agent Parser

Read the browser, engine, OS and device out of a UA string.

Everything runs inside your browser. Your files never leave your device.

Input

Result

The result appears here as you type.

Ask about User Agent Parser

Questions about what this tool does, which option to pick, or what it can and cannot handle.

The question you type here is sent to an AI provider to be answered — your files and whatever you put in the tool above are not, and the assistant cannot see them. Answers are generated and can be wrong. The tool itself is not guessing: it runs deterministic code on your device.

About the User Agent Parser

A user-agent string is a sentence a browser tells about itself, and most of that sentence is a historical lie. Nearly every browser claims to be Mozilla; Chrome claims to be Safari; Edge claims to be both and then adds itself at the end. Each of those claims was added to get past a compatibility check written decades ago, and none has ever been removed.

This parser untangles it. Paste a string and it names the browser and version, the rendering engine, the operating system and version, and the device category. It also flags automated clients — search crawlers, AI crawlers, link-preview fetchers, and the command-line tools that make no attempt to pretend.

Order is everything in doing this correctly. Because every Chromium browser also declares itself as Chrome and as Safari, matching Chrome first would identify Edge, Opera, Samsung Internet and Brave all as Chrome. The parser checks the most specific token first and works outwards, which is why Edge is reported as Edge here and as Chrome by a great many parsers that do it the other way round.

The important caveat is on the page itself, not hidden in a footnote. Every part of this string is chosen by the client and none of it is verified. A crawler claiming to be Googlebot may not be Googlebot — confirming that requires a reverse DNS lookup on the connecting address. Browsers are also freezing these strings deliberately: Chrome no longer reports a meaningful minor version and Safari reports a fixed WebKit build, both as anti-fingerprinting measures.

So parse a user-agent to understand traffic you have already received. Do not branch your application on it. Feature detection tells you what the browser can actually do, and the Sec-CH-UA client hints give you the same facts through a channel designed for the purpose.

How to use it

1Paste the user-agent string, with or without the leading “User-Agent:” header name.
2Read the breakdown — browser, engine, operating system, device.
3Check the notes underneath, which say what the string can and cannot be trusted to tell you.
4Switch to JSON if the result is going into a script or a log-analysis pipeline.

Questions

Why does every browser claim to be Mozilla?: A compatibility check from the 1990s tested for it before serving modern content. Browsers added the token to pass, and it has never been safe for any of them to remove. The same history explains why Chrome claims Safari and Edge claims both.
Can I trust that a request really came from Googlebot?: No. Anyone can send that string. Verifying it means a reverse DNS lookup on the connecting IP address followed by a forward lookup on the result — Google documents the procedure, and it is the only reliable check.
Why does the version look truncated?: Because it is. Chrome freezes the minor version components and reports the major version only, and Safari reports a fixed WebKit build number, both to reduce fingerprinting. There is no more detail available to extract.
Should I use this to decide what to serve?: No. Feature-detect instead, or read the Sec-CH-UA client hints. Branching on a user-agent breaks silently every time a browser changes its string, and browsers change their strings specifically to break that pattern.