User agent strings are an archaeological record of browser history — nearly every browser still claims to be Mozilla for compatibility reasons dating back to the 1990s. This parser extracts the browser, rendering engine, operating system, and device type from your own string or any one you paste in.
Historical compatibility. Servers in the 1990s sniffed for Mozilla before sending modern HTML, so every browser adopted the prefix and none has been able to drop it since.
Not really. Strings are trivially spoofed, browsers freeze parts of them for privacy, and Chrome is actively reducing their detail. Feature detection is the correct approach for anything functional.
The modern replacement: the browser sends structured Sec-CH-UA headers, and the server requests extra detail only when it genuinely needs it. Far more privacy-friendly than a single fingerprintable string.
Because they share engine lineage and each added tokens to avoid being served degraded pages. The result is a string that names four browsers and identifies one.
All free tools · Blog · About · Contact