Calculator
What the User Agent Parser does
User Agent Parser: calculates Status and Parsed JSON from User-Agent string. Example: the sample loaded on the page gives status Parsed.
Give the User Agent Parser your User-Agent string and it works out Status and Parsed JSON. There is no submit step; the numbers move as you adjust them.
It is mostly used by engineers checking an encoding. Pasting a production payload into an unknown web tool is a real risk, which is why this one stays local.
Nothing is uploaded: useful when the text you are inspecting contains keys or customer records.
The field table, the method and a worked example are documented after the tool for anyone who wants to check the working.
What do the User Agent Parser fields mean?
The User Agent Parser uses 1 input. Rather than an empty form you get a filled one, useful when you only want to test a single change.
| Field | What to enter | Default |
|---|---|---|
| User-Agent string | paste or type any amount of text | Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 |
How does the User Agent Parser work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same calculation.
Bad input produces an error, never a confident-looking wrong answer.
Worked example
These are the values the User Agent Parser loads by default, and the result it produces from them. The defaults produce the result shown here; change any of them and the answer moves.
| User-Agent string | Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537… |
|---|
| Status | Parsed |
|---|---|
| Parsed JSON | { "browser": "Chrome", "os": "Windows", "mobile": false, "length": 111 } |
How to use it
- Paste your content into User-Agent string.
- Because there is no round trip to a server, updating on every keystroke costs nothing.
- Check Status and Parsed JSON on the right.
- If you need a record, Copy Link saves the inputs and Print produces a clean page.
What this tool does not do
- Processing happens in your browser, so extremely large inputs are bounded by available memory.
- Output follows the common convention for this format; a specific toolchain may have its own house style.
- The tool answers exactly the question it is given; it cannot know the context around your numbers.
Frequently asked questions
You need User-Agent string. A starting value is in place for each, so the form is usable immediately, without filling anything in first.
With the values loaded when the page opens, status comes out as Parsed. Edit any input and that figure moves with it.
No. The work runs in JavaScript inside this page, so your values never leave your device. You can confirm it in your browser network tab.
No cost and no account. Use it as often as you like.
The computation is exact; how much you should trust the answer depends on how good your inputs are.