JSON Formatter & Validator
Format, validate, and minify JSON — all in your browser, nothing sent to servers
Input
Output
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What is a JSON Formatter?
A JSON formatter takes raw or compressed JSON text and adds indentation and line breaks to make it human-readable. JSON (JavaScript Object Notation) is a lightweight data format used extensively in APIs, configuration files, and web applications. When JSON comes from an API or gets minified for production, it's often a single long line with no whitespace — difficult to read and debug.
This tool does the reverse too: minifying takes pretty-printed JSON and removes all unnecessary whitespace, producing the smallest possible output for production use. All processing happens in your browser — your data is never sent to any server.
How to Use This Tool
- Paste your JSON into the Input area on the left (or type directly).
- Click "Format / Beautify" to add readable indentation, or "Minify" to compress it.
- Click "Validate" to check if your JSON is syntactically valid — the tool shows the exact line and character of any error.
- Copy the output using the "Copy Output" button.
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Frequently Asked Questions
Yes, completely. This tool runs entirely in your browser using JavaScript. No data is transmitted to any server — everything stays on your device. You can verify this by disconnecting from the internet and observing that the tool still works perfectly. This makes it safe to use with API keys, credentials, or any sensitive configuration data.
Formatting (beautifying) adds indentation and line breaks to make JSON readable to humans. Minifying does the opposite — it removes all whitespace that isn't inside string values, producing the smallest possible file size. Use formatted JSON for development and debugging; use minified JSON in production APIs to reduce bandwidth and improve load times.
Common JSON errors include: trailing commas after the last item in an object or array (not allowed in standard JSON), single quotes instead of double quotes for strings, unquoted keys, missing commas between items, and comments (JSON does not support // or /* */ comments). The validator shows the exact line and position of the error to help you locate it quickly.
JSON is a text format derived from JavaScript object syntax, but with stricter rules: all keys must be double-quoted strings, trailing commas are not allowed, functions and undefined are not valid values, and comments are not supported. A JavaScript object literal like
{ name: 'John' } is valid JS but invalid JSON. Valid JSON requires { "name": "John" }.Yes. Use the "Indent" dropdown to select tab indentation instead of spaces. You can also choose between 2-space and 4-space indentation. The choice is purely cosmetic — all three produce valid, equivalent JSON. Most style guides for JavaScript projects prefer 2 spaces for JSON files to keep line lengths manageable.