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User Agent Parser

Read any user agent string as browser, operating system, device type, and rendering engine, starting with your own.

Prefilled with your own browser and parsed live as you type. Nothing leaves your browser.

How to parse a user agent string

  1. Start with your own

    The field opens prefilled with the user agent your browser is sending right now, already broken down below.

  2. Paste a different string

    Replace it with a user agent from a log line, a bug report, or a support ticket, and the breakdown updates as you type.

  3. Read the breakdown

    Browser and version, operating system, device type, and rendering engine each sit on their own row, with the raw string below.

  4. Copy what you need

    Copy a single field, or copy the whole breakdown as JSON to paste into a ticket or a test fixture.

Why use this tool

Prefilled with your own browser

Open the page and your current user agent is already there and already parsed, so answering "what is my user agent" takes no typing.

Four fields that matter

Browser and version, operating system with its version where the string carries one, device type, and rendering engine.

Bots labelled as bots

Search crawlers, link previewers, and command line clients are recognised and marked as automated rather than dressed up as a browser.

Degrades instead of failing

A trimmed, custom, or nonsense string returns Unknown for the parts it cannot place, with the rest still filled in. Nothing errors out.

Copy a field or the whole thing

Every row has its own copy button, and the full breakdown copies as JSON for a bug report or a test fixture.

Runs entirely in your browser

Parsing happens on your device against a built-in rules table. No lookup service is contacted and nothing is uploaded.

About this tool

A user agent string is the line a browser sends with every request to describe itself, and it is one of the strangest strings in computing. Almost every browser still starts with Mozilla, most claim to be Safari, and Chromium browsers claim to be Chrome as well as themselves. That history is why the raw string is nearly unreadable and why a parser has to work through the most specific markers first. This tool does exactly that and shows you the four things you usually want: browser and version, operating system, device type, and rendering engine such as Blink, Gecko, or WebKit.

The field starts prefilled with the user agent your own browser is sending, so the common question of what am I actually reporting is answered on arrival. Replace it with a string from a server log, an analytics export, a bug report, or a support ticket, and the breakdown updates as you type. Search crawlers, link preview fetchers, and command line clients are recognised and labelled as bots, which is often the whole point of the lookup: working out whether a strange traffic spike was people or machines.

Treat every result as a claim rather than a fact. A user agent is set by whoever sends the request, so it can be trimmed, faked, or made up entirely, and modern browsers deliberately freeze parts of it to reduce fingerprinting. Windows in particular reports only a kernel version, so 10 and 11 are indistinguishable. When a string carries nothing recognisable, the affected rows read Unknown instead of guessing. For neighbouring pieces of a request, see the URL parser, the JWT decoder, and the HTTP status codes reference.

Frequently asked questions

What is a user agent string?
It is a line of text your browser sends with every request, describing the browser, its version, the operating system, and the rendering engine. Servers use it for analytics, for compatibility workarounds, and for telling people apart from crawlers.
Why does my user agent say Mozilla and Safari when I use Chrome?
For historical compatibility. Sites once sniffed for specific browsers to decide which features to send, so browsers started claiming to be each other to avoid being locked out. Those claims were never removed, which is why one string can name three browsers at once.
Can a user agent be faked?
Yes, easily. It is set by whoever sends the request, so it can be changed in developer tools, in an extension, or in a script. Read the result as what the client claims, not as proof of what it is, and never use it as a security control.
Why is the operating system version missing or vague?
Because the string often does not carry it. Windows reports a kernel version rather than a name, so 10 and 11 look identical, and browsers now freeze or round parts of the string to reduce fingerprinting. Missing pieces are shown as Unknown rather than guessed.
Is anything uploaded when I parse a string?
No. Parsing runs in your browser against a built-in rules table, so no lookup service is contacted and the string never leaves your device. That matters when the user agent came from a customer log line.

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