JSON Formatter
Format & validate JSON
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What Is This Tool?
The JSON Formatter takes messy, minified, or hand-written JSON and re-indents it into a clean, readable structure with 2-space indentation. It also validates the JSON as it formats, so syntax mistakes are caught immediately instead of surfacing later as a cryptic server error. Everything runs locally in your browser — nothing you paste is ever uploaded or stored.
How to Use
Paste or type your JSON into the input box.
Click Format to pretty-print it, or Minify to compress it to one line.
Use Validate to check syntax without changing the output.
Copy the result or download it as a .json file.
Features
- Instant formatting with 2-space indentation
- One-click minification for compact payloads
- Clear line/column error reporting on invalid JSON
- Live character and line counters
- Copy to clipboard or download as a file
- 100% client-side — nothing leaves your browser
Examples
Before (minified):
{"name":"Ada","active":true,"roles":["admin","editor"]}
After (formatted):
{
"name": "Ada",
"active": true,
"roles": [
"admin",
"editor"
]
}
Common Use Cases
- Cleaning up an API response before reading it
- Minifying JSON config before shipping it to production
- Debugging a malformed JSON payload from logs
- Preparing readable JSON examples for documentation
Frequently Asked Questions
Is my JSON uploaded anywhere?
No. All formatting and validation happens locally in your browser using JavaScript. Nothing is sent to a server.
What indentation does Format use?
Format always re-indents with 2 spaces per nesting level, which is the most common convention for JSON.
How do I make JSON as small as possible?
Click Minify. It removes all unnecessary whitespace so the JSON is valid but takes up minimal space.
Why does it say my JSON is invalid?
The tool shows the exact line and column where parsing failed. Common causes are trailing commas, single quotes instead of double quotes, or unquoted keys.
Is there a size limit?
There's no hard limit, but very large documents (several megabytes) may be slow to format since everything runs in your browser's JavaScript engine.
Can I download the formatted result?
Yes, click Download to save the current output as a data.json file.