JSON Formatter
Format and beautify JSON with syntax validation and repair.
About this tool
Messy or minified JSON in, indented JSON out. Validates syntax as you go and can repair common issues like trailing commas — useful for API debugging, config review, and documentation.
Paste a response from DevTools, a log line, or a compressed package.json. Pair with JSON Validator for precise error locations or JSON Minifier when you need a compact payload.
Runs in your browser. Sensitive data never leaves your device.
How to use
- Paste compact or messy JSON into the Input editor (trailing commas and minor syntax issues are often repairable).
- Click Format to pretty-print with 2-space indentation.
- Scan the Output pane for nested structure, then use Copy or Download when it looks right.
- If you see an error, fix the reported syntax issue and Format again.
Example
Pretty-print an API config blob
Input
{"service":"billing","retries":3,"features":{"webhooks":true,"batch":false}}Output
{
"service": "billing",
"retries": 3,
"features": {
"webhooks": true,
"batch": false
}
}The formatter also attempts light repair (e.g. trailing commas) before pretty-printing.
Limitations
- Repair is best-effort — deeply broken or ambiguous JSON may still fail to parse.
- Very large payloads can feel slow in the browser; split or stream them in your own tooling for multi-MB files.
- Formatting does not validate against a schema; use the JSON Schema Validator for that.
Related guides
1Related tools
3Frequently asked questions
What does the JSON Formatter do?
Format and beautify JSON with syntax validation and repair. Runs in your browser — no install, no account.
How do I use the JSON Formatter?
Paste compact or messy JSON into the Input editor (trailing commas and minor syntax issues are often repairable). Click Format to pretty-print with 2-space indentation. Scan the Output pane for nested structure, then use Copy or Download when it looks right. If you see an error, fix the reported syntax issue and Format again.
Is the JSON Formatter free?
Yes. No signup, no usage limits, no paywall.
Does the JSON Formatter upload my data?
No. Processing happens locally in JavaScript. Your input is not uploaded, stored, or logged.
What are the limitations of the JSON Formatter?
Repair is best-effort — deeply broken or ambiguous JSON may still fail to parse. Very large payloads can feel slow in the browser; split or stream them in your own tooling for multi-MB files. Formatting does not validate against a schema; use the JSON Schema Validator for that.