What is a User-Agent string?

A User-Agent string is a text that your browser sends to websites to identify itself, including the browser name, version, operating system, and device type.

Why do websites need my User-Agent?

Websites use your User-Agent to deliver content optimized for your browser and device. It helps them serve the right layout, format, and features for your setup.

Can I change my User-Agent?

Yes, most browsers allow you to change your User-Agent through developer tools or browser extensions. This is called User-Agent spoofing and is often used for testing.

Is my User-Agent unique?

Your User-Agent alone is usually not unique since many people use the same browser and OS. However, combined with other browser data, it can contribute to a unique fingerprint.

Is this User-Agent checker free?

Yes, this User-Agent checker is completely free. No account, no signup, and no payment required. All detection runs locally in your browser.

User-Agent Checker

Your User-Agent string reveals information about your browser, operating system, and device. See exactly what websites can detect about you.

Your User-Agent String

Parsed Information

Browser Capabilities

HTTP Headers (Client-Side)

These headers are typically sent by your browser with every request. Some can only be detected server-side.

What is a User-Agent?

A User-Agent string is an HTTP header that your browser sends to every website you visit. It identifies your browser type, version, operating system, and other technical details about your device.

Why Websites Use User-Agent

Content Adaptation: Serve mobile-optimized pages to mobile devices.
Browser Compatibility: Adjust features or styling based on browser capabilities.
Analytics: Track which browsers and devices visitors use.
Security: Block or warn users of unsupported browsers with known vulnerabilities.

Privacy Concerns

Your User-Agent contributes to your browser fingerprint. Combined with other attributes like screen resolution, installed fonts, and timezone, it can help identify you uniquely across websites — even without cookies.

How does this tool work?

This tool reads your browser's User-Agent string directly from the navigator.userAgent property — no server requests are needed. It then parses the string to extract structured information about your browser, operating system, and device. Additionally, it tests several browser capabilities (JavaScript, cookies, WebGL, etc.) and displays relevant HTTP headers available from the client side.

Why should you check your User-Agent?

Debugging: Verify what User-Agent your browser is sending to websites.
Privacy: Understand how much information your browser leaks about your device.
Compatibility testing: Ensure your User-Agent is correctly formatted for web development.
Security: Check if your browser is identifying itself with an outdated or unusual string that could cause issues.

How to Change Your User-Agent

Browser DevTools: Most browsers allow you to override the User-Agent in developer tools (F12 → Network conditions).
Browser Extensions: Extensions like "User-Agent Switcher" let you set custom UA strings.
Tor Browser: Standardizes the User-Agent for all Tor users, making you blend in.
Firefox Settings: You can modify general.useragent.override in about:config.