JSON Formatter
Format and indent JSON, or minify it. Invalid JSON gets an error that points at the problem.
How to use this tool
- Select your file, drag it onto the box above.
- Processing starts automatically — there is nothing to configure.
- Check the result panel, which shows the original size, the final size and the page count.
- Click Download to save it.
When parsing fails, the tool reports the line and column, shows the surrounding text, and lists the usual culprits — a trailing comma, single quotes, or an unquoted key. That is faster than hunting through the browser console.
The specification
| Indent | 2 spaces, 4 spaces, tab, or minified |
|---|---|
| Validation | Reports line, column and context on failure |
| Stats | Type, key count, size before and after |
| Processing | Entirely in your browser |
How it works
This tool runs entirely in your browser. There is no server involved, which means nothing you type or upload is transmitted, stored, or logged — and there are no usage limits, because there is nothing for us to ration.
You can confirm it yourself: open your browser's developer tools, select the Network tab, and use the tool. No request is made.
Who uses this
Reading an API response, tidying a configuration file, or minifying JSON before embedding it.
Frequently asked questions
Why is my JSON invalid?
The most common causes are a trailing comma before a closing brace or bracket, single quotes instead of double quotes, unquoted keys, and unescaped newlines inside strings. The error message points at the exact position.
Is my data sent to a server?
No. Parsing uses your browser’s built-in JSON engine. Nothing is transmitted — which matters, because API responses often contain credentials or personal data.
What is the difference between JSON and JavaScript objects?
JSON requires double-quoted keys and strings, forbids trailing commas, comments, and values such as undefined or NaN. Valid JavaScript is frequently invalid JSON.
Are my files uploaded to a server?
No. Everything runs inside your browser on your own device. Your file is never transmitted and never stored by us. You can confirm this by opening your browser’s Network tab while you use the tool — you will see no upload request.
Is there a limit on how many files I can process?
No. There is no daily cap, no account, and no watermark. Because the work happens on your device rather than our servers, there is nothing for us to ration.
Is this tool really free?
Yes — no account, no trial, no watermark, and no cap on usage. It runs on your own device rather than our servers, so there is no cost for us to pass on.
Does it work on mobile?
Yes. The interface adapts to phone and tablet screens, and everything runs in the browser, so there is no app to install.
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Your files stay on your device. This tool runs entirely in your browser. No file is uploaded, transmitted, or stored. You can verify this by opening your browser's Network tab while using the tool.
Disclaimer. Specifications published by exam boards, governments and platforms change without notice. We verify and date every specification on this site, but you should always confirm against the official source before submitting an application. See our full disclaimer.