This tool instantly answers the question “what is my user agent?” by detecting your user agent string and showing exactly what your browser reveals to every website you visit. Your user agent identifies your browser name and version, operating system, device type, and rendering engine. Understanding what is in your user agent helps you verify your browser’s identity, troubleshoot website compatibility issues, and assess your privacy exposure.

What Is a User Agent?

A user agent is a string of text that your browser sends to every website you visit as part of the HTTP request headers (defined in RFC 7231). It identifies your browser, operating system, device type, and rendering engine. Websites use this information to deliver optimized content, track browser statistics, and troubleshoot compatibility issues. When you ask “what is my user agent?” you are asking what identification string your browser is currently broadcasting.

User Agent Components

Browser — The name and version of your web browser (Chrome, Firefox, Safari, Edge, etc.).

Rendering Engine — The engine that processes HTML and CSS. Chrome and Edge use Blink, Firefox uses Gecko, and Safari uses WebKit.

Operating System — Your OS and version, such as Windows 11, macOS Ventura, Ubuntu Linux, Android 14, or iOS 17.

Device Type — Whether you are on a desktop, mobile phone, tablet, or a bot/crawler.

Common User Agent Examples

Modern user agent strings follow a complex format that has evolved over decades. If you have ever wondered what is my user agent composed of, here are examples from major browsers:

Chrome on Windows: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36
Firefox on macOS: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:121.0) Gecko/20100101 Firefox/121.0
Safari on iPhone: Mozilla/5.0 (iPhone; CPU iPhone OS 17_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 Mobile/15E148 Safari/604.1
Googlebot: Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)

Most browsers include “Mozilla/5.0” at the start for historical compatibility reasons, even though they are not Mozilla Firefox.

Why User Agents Matter

Web developers use user agents to serve different content to different devices (responsive design), detect outdated browsers, and identify crawlers. Analytics platforms parse user agents to report browser and OS usage statistics. API providers may use user agents to identify client applications and enforce rate limits. Knowing what is my user agent can also help you understand why certain websites render differently in your browser.

User Agents and Privacy

Your user agent string contributes to browser fingerprinting — a technique websites use to track users without cookies. The combination of your browser version, OS, screen resolution, installed plugins, and other factors creates a nearly unique fingerprint. Some privacy-focused browsers like Brave and Tor Browser reduce user agent information to make fingerprinting harder. Chrome has also introduced Client Hints as a more privacy-friendly alternative to the traditional user agent string.

Bot and Crawler User Agents

Search engines and automated tools identify themselves through user agent strings. Googlebot, Bingbot, and other crawlers include their name and a URL with more information. Web application firewalls and analytics tools parse user agents to distinguish between legitimate bots and malicious scrapers. Knowing how bots identify themselves helps you understand your server logs and configure crawl access rules.

User Agent Client Hints

Modern browsers are moving toward User Agent Client Hints (UA-CH), a newer API that replaces the traditional user agent string with structured, opt-in headers. Instead of sending all information by default, the server requests only the specific details it needs (e.g., browser brand, platform, or mobile status). This reduces the amount of information passively leaked to websites and makes the answer to “what is my user agent?” less revealing by default.

Spoofing and Modifying User Agents

User agents can be changed using browser developer tools, extensions, or custom HTTP clients. Developers often spoof user agents to test how a website responds to different browsers or to access mobile-only content from a desktop. However, user agent spoofing can also be used for malicious purposes like scraping or bypassing access controls, which is why it should not be the sole factor in security decisions.

Related Tools

Your user agent is just one of many HTTP headers your browser sends. Use our HTTP Header Checker to see all response headers a website sends back. To analyze email routing headers, try our Email Header Analyzer.

What Is My User Agent