What is my browser?

What is a browser, and how does it identify itself?

A browser is the application you use to navigate the web — Chrome, Firefox, Safari, Edge, and Opera are the most common. When your browser makes a request to a website, it automatically includes a short text string called the User-Agent in the request headers. This string contains your browser's name and version, your operating system, and sometimes additional details.

This happens with every single request — page loads, image downloads, API calls. The website receives it before any of your content has loaded, before you've clicked anything, and without needing any permission from you. It is part of how HTTP, the protocol the web runs on, was designed.

The User-Agent string is what makes the BROWSER field above possible. No special access or permission is required — the value shown is exactly what your browser sends to every site you visit.

Why do websites use browser information?

The primary reason is compatibility. Browsers implement web standards at different rates and with different quirks. Developers use the browser name and version to detect whether a visitor's browser supports a particular feature, and to serve fallback code or layouts when it does not. This is why a site might look slightly different in an older browser than a current one.

Analytics is another common use. Website owners track which browsers their visitors use to inform decisions about which browsers to support and test — if 30% of their audience is on Safari and they only test in Chrome, they risk a poor experience for a large group.

Browser information is also used in fraud detection. Inconsistencies between the reported browser, operating system, and other signals can be a signal that something is unusual about a session — for example, a User-Agent reporting a mobile browser while other signals suggest a desktop environment.

Browser fingerprinting

No single piece of browser data uniquely identifies a person. But when multiple signals are combined — browser name and version, language preference, screen size, timezone, installed fonts, and others — the resulting profile can be distinctive enough to recognize a returning visitor even without storing any cookie on their device.

This technique is called browser fingerprinting. It works because the combination of all these values is often statistically uncommon — there are not many users with the exact same browser version, language setting, screen resolution, and timezone all at once.

Fingerprinting is used for both legitimate purposes (fraud prevention, bot detection) and for tracking across sites without consent. Privacy-focused browsers and extensions try to reduce fingerprinting surface by standardizing or randomizing some of these signals. Your OS, device type, and screen resolution also contribute to this profile — see our OS page and screen resolution page →

How people manage browser privacy

Privacy-focused browsers such as Firefox, Brave, and others ship with stronger default settings around tracking — blocking third-party cookies, limiting what fingerprinting data is accessible, and in some cases spoofing or standardizing the User-Agent string to make users less individually identifiable.

Disabling third-party cookies limits one common tracking method — cookies set by advertising or analytics networks that follow you across sites. Most major browsers now block third-party cookies by default or have announced plans to do so.

Do Not Track is a browser setting that sends a signal to websites asking them not to track your behavior. In practice, it is voluntary and most services do not honor it, so it offers limited real-world protection — though some privacy regulations in certain regions do require sites to respect it.

Private or incognito mode prevents your browser from saving history, cookies, and form data locally after the session ends. It does not hide your browser identity from websites — your User-Agent, language, and other signals are still transmitted normally during the session.