How to Parse a User-Agent String Into Browser & OS

To parse a User-Agent string, paste it into the User Agent Parser and it uses pattern matching to report the browser and version, the rendering engine, the operating system, and the device type. The tool loads prefilled with your own User-Agent, so you see a working result the moment the page opens, and everything runs locally in your browser.

A User-Agent string is a dense, oddly formatted header, and reading it by eye is confusing. This guide explains what it contains and how to break it down cleanly.

What a User-Agent string contains

Your browser sends a User-Agent header with every request to identify itself. Packed into that one line are the browser name and version, the engine that renders pages, and the operating system. The parser pulls out the four values you usually care about.

Step-by-step: parse a UA string in the browser

1. Open the tool — your current browser's User-Agent is already filled in, so a result shows straight away.
2. Paste a different User-Agent to analyse another client, for example one copied from an analytics log or a bug report.
3. Read the detected values: browser and version, rendering engine, operating system, and device type.
4. Copy any value you need into your notes, ticket, or documentation.

Because parsing runs instantly as you paste, you can compare several UA strings one after another without any waiting.

Why Chrome's UA mentions Safari and Mozilla

New users are often thrown by a Chrome string that also says Mozilla, AppleWebKit, and Safari. These are legacy compatibility tokens that nearly every browser carries for historical reasons. The parser accounts for them and reports the actual browser rather than being misled, which is one of the main reasons using a tool beats reading the raw string yourself.

Why in-browser parsing keeps data private

The tool matches patterns locally using a set of heuristic regular expressions rather than calling an external service. Nothing you paste is transmitted anywhere, so a UA string lifted from a server log or a private bug report stays on your device. It also means the parser works offline once loaded and needs no library, API key, or account.

Try the User Agent Parser — free and 100% in your browser.

FAQ

How do I find my own User-Agent?

You do not have to look anywhere else. The input is prefilled with your current browser's User-Agent the moment the page loads, so you can read and copy it directly.

What does the rendering engine tell me?

The engine, such as Blink, WebKit, Gecko, or Trident, determines how a page is drawn and which quirks to expect. It is useful when a layout bug appears only on browsers sharing one engine.

Can it detect whether a client is mobile?

Yes. The parser classifies the device as desktop, tablet, or mobile based on the string, which helps when you are separating traffic types in a log.

Does it need an internet connection?

No. Once the page has loaded, parsing happens entirely on your device, so it continues to work offline as a browser-based tool.

Related free tools

• HTTP Status Code Lookup — decode response codes while debugging.
• URL Parser — break a request URL into components.
• Query String Parser — inspect query parameters in a link.
• MIME Type Lookup — identify content types by extension.

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