Is the User-Agent string sent anywhere?

No. Parsing uses local regular expressions in your browser. The string — including your own — is never sent to a server.

How accurate is the detection?

Detection uses an ordered set of regular expressions that test specific tokens before generic ones (for example Edge before Chrome). It is a best-effort parse, and User-Agents can be spoofed, so treat the result as a strong guess rather than proof.

Why is my browser shown as Safari or Chrome unexpectedly?

Many User-Agents intentionally include legacy tokens like "Safari" or "Mozilla" for compatibility, and embedded browsers reuse engine names. The parser reports the most specific match it can find from those tokens.

What is a User-Agent string?

It is a text header your browser sends with every request, identifying the browser, its version, the rendering engine and the operating system — for example Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0 Safari/537.36. Servers use it to tailor responses.

What is the difference between a browser and a rendering engine?

The browser is the application (Chrome, Firefox, Safari); the rendering engine is the component that turns HTML and CSS into pixels (Blink, Gecko, WebKit). Several browsers share one engine — Chrome and Edge both use Blink, for instance.

Why does Chrome's User-Agent contain the word Safari?

For historical compatibility. Chrome was built on WebKit and kept the AppleWebKit and Safari tokens so that sites sniffing for Safari would serve it correctly. The parser tests for Chrome before Safari so it still reports Chrome.

Can a User-Agent be faked?

Yes. The string is self-reported and can be changed or spoofed by browser settings, extensions, scrapers and bots. Treat any parsed result as a strong guess, not proof of the actual software.

How does the parser detect bots?

It looks for known crawler tokens such as bot, spider or specific names (Googlebot, bingbot) in the string and labels the device type as a bot when one matches.

User-Agent Parser — Gera Tools

User-Agent parser

Every time a browser makes a request, it sends a User-Agent string — a line of text that names the browser, its version, the rendering engine and the operating system. This parser breaks any such string into those parts: browser, rendering engine, operating system and device type (desktop, mobile, tablet or bot). The box is pre-filled with your own browser’s User-Agent so you can see exactly what your device reports, and you can paste strings from logs or analytics to identify what generated each request.

How it works

Detection runs an ordered set of regular expressions against the string, testing the most specific tokens before the generic ones. This ordering matters because User-Agents deliberately overlap: a Chrome string also contains Safari, and an Edge string also contains Chrome. By checking Edg/ before Chrome/, and SamsungBrowser/ before plain Chrome/, the parser reports the most precise match. It separately matches OS tokens (Windows, macOS, Android, iOS, Linux) and device hints to classify the device.

Example

Given Mozilla/5.0 (iPhone; CPU iPhone OS 17_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Mobile/15E148 Safari/604.1, the parser reports:

Field	Detected
Browser	Safari 17.0
Engine	WebKit
OS	iOS 17
Device	Mobile

Everything runs in your browser; no string is sent to a server. Because User-Agents are self-reported and can be spoofed, treat the output as a best-effort interpretation rather than proof.