User Agent Finder & Parser

Find your web browser user agent metadata instantly. Paste and parse custom browser agent strings offline securely.

Your Current User Agent String

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System & Environment Details

Operating System Detecting...

Browser & Version Detecting...

Device Category Detecting...

Rendering Engine Detecting...

Inspect Custom User Agent

Pasted User Agent String

Parsed Details

Operating System -

Browser & Version -

Device Category -

Rendering Engine -

What is a User Agent and How does it Work?

A **User Agent** is a unique text identification string that your web browser transmits to web servers inside HTTP headers on every connection request. This string contains specific metadata outlining the browser name, revision version numbers, hosting layout rendering engine (like Blink or WebKit), operating system, and target device (Mobile vs Desktop). Web servers read this string to dynamically serve responsive page content or enforce access redirects.

Parsing user agents is critical for SEO debugging, verifying web bot crawler crawls (such as Googlebot), analyzing diagnostic system reports, and auditing responsive visual configurations. This utility runs entirely client-side using JavaScript regex matching, protecting private connection strings from database logging trackers.

Frequently Asked Questions (FAQ)

Why do all user agents start with "Mozilla/5.0"?

Historically, this prefix was added during the browser wars of the 1990s. Netscape (Mozilla) supported frames while other browsers did not. To bypass server restrictions that only allowed Netscape connections, other browsers began adding "Mozilla" to their agent strings. This legacy practice remains active today for compatibility.

What is a Rendering layout engine?

A rendering engine is the software module that compiles HTML/CSS structures and paints pixels visually on your screen. Major engines include **Blink** (powering Chrome, Edge, and Opera), **WebKit** (powering Safari on iOS/macOS), and **Gecko** (powering Firefox).

Can I forge or modify my User Agent?

Yes. Most modern web browsers allow developers to override or "spoof" user-agent strings inside DevTools settings. This is useful for testing mobile layout rendering speeds or auditing custom user agent redirect rules offline.