What is a user agent string?

A user agent (UA) string is a text identifier sent by your browser to every web server you visit. It tells the server which browser, operating system, and device you are using so the server can serve appropriate content.

Why do websites check the user agent?

Websites use the user agent to serve mobile-optimized layouts, apply browser-specific CSS fixes, block bots, and tailor content. Some analytics tools also rely on UA parsing to report browser and device stats.

Can I change my user agent?

Yes. Most browsers allow you to spoof a different user agent through developer tools (usually under Network conditions). Browser extensions can also override the UA header on all requests.

Is my user agent sent to Irreva?

No. This tool reads your user agent directly from the browser's navigator.userAgent property in JavaScript. Nothing is sent to Irreva's servers.

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

The rendering engine (Blink, WebKit, Gecko) is the underlying technology that interprets HTML, CSS, and JavaScript. Multiple browsers can share the same engine — for example, Chrome, Edge, and Opera all use Blink.

User Agent Checker — Detect Browser, OS & Device Free Online

Detect your browser name, version, OS, device type, and rendering engine from your user agent string. Analyze any custom UA. Free, instant.

User agent detection runs entirely in your browser. No data is sent to any server.

100% Private

No Upload

Instant

What is User Agent Checker?

A user agent checker parses the HTTP user agent string that your browser sends with every web request, extracting structured information about your browser name and version, operating system, device type (desktop, mobile, tablet), and rendering engine (Blink, Gecko, WebKit). You can also paste any custom user agent string to analyze it — useful for testing browser detection logic and debugging crawlers.

How to Use User Agent Checker

1Open the tool — your current user agent is detected automatically.
2View your browser, OS, device type, and rendering engine.
3To analyze a different user agent, paste it into the input field.
4Click Analyze to parse the custom user agent string.
5Review the structured breakdown of all detected components.

Key Features

Auto-detects your current browser's user agent
Browser name and version extraction
OS name and version detection
Device type detection (desktop, mobile, tablet, bot)
Custom user agent string analysis

Benefits

Verify how your site detects your browser and device
Test user agent strings for browser detection logic
Debug issues affecting specific browser or OS combinations
Analyze crawler and bot user agent strings

Why Use Irreva for User Agent Checker?

Verify how your site detects your browser and device

Test user agent strings for browser detection logic

Debug issues affecting specific browser or OS combinations

Runs 100% in your browser — files never leave your device.

No account, no sign-up, no subscription — free forever.

Works on any device: desktop, tablet, or mobile.

Frequently Asked Questions

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