Why does Chrome's User-Agent mention Safari and Mozilla?

Historical accretion. Early sites served different pages based on the User-Agent, so each new browser claimed compatibility with the established ones to avoid being blocked, layer upon layer — which is why Chrome's string contains Mozilla, AppleWebKit, KHTML, and Safari. Parsing has to start from the most specific brand.

Can a User-Agent identify a user?

No. It is entirely client-supplied and can be set to any value; browser extensions and command-line tools change it in one step. It is fine for aggregate statistics and non-critical experience tweaks, but it must never be used for access control or authentication.

NETWORK TOOLS · NO PACKETS ARE SENT

User-Agent Parser

Break down a User-Agent string into browser, engine, operating system, and device type.

Input

User-Agent string

BrowserChrome 131.0.0.0

Operating systemmacOS 10.15.7

Results

BrowserChrome 131.0.0.0

Layout engineBlink 537.36

Operating systemmacOS 10.15.7

Device typeDesktop

Looks like a bot—

String length117

A User-Agent is client-supplied and can be set to anything. Never use it for access control or authentication.

About this tool

Paste a User-Agent string to get the browser name and version, the layout engine, the operating system and version, the device type, and whether it looks like a bot. The match order runs from specific to general on purpose: every Chromium browser also claims to be Chrome, and Chrome claims to be Safari, so Edge and Opera must be tested first or everything collapses into Chrome. You can also load the current browser's own string to compare.

How it works

Paste a User-Agent string, or load the current browser's.
Read the browser, engine, operating system, and device.
Check whether it was classified as a bot.

Limits and notes

Pure pattern matching; the string is never executed. A User-Agent can be set to anything, so it is not evidence of identity.

Privacy

Addresses and strings are calculated inside this browser only. Nothing is uploaded, stored, or written to the URL or any log.

Frequently asked questions

Why does Chrome's User-Agent mention Safari and Mozilla?: Historical accretion. Early sites served different pages based on the User-Agent, so each new browser claimed compatibility with the established ones to avoid being blocked, layer upon layer — which is why Chrome's string contains Mozilla, AppleWebKit, KHTML, and Safari. Parsing has to start from the most specific brand.
Can a User-Agent identify a user?: No. It is entirely client-supplied and can be set to any value; browser extensions and command-line tools change it in one step. It is fine for aggregate statistics and non-critical experience tweaks, but it must never be used for access control or authentication.

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