Beautify, validate, and minify JSON data. Features syntax highlighting and error detection.
Paste your raw JSON string into the editor.
Click "Beautify" to format it with proper indentation.
Click "Minify" to remove whitespace for production use.
Use the Copy or Download buttons to save your result.
No — all validation and formatting runs locally in your browser using JavaScript. Your JSON data never leaves your device.
Beautify adds indentation and line breaks for human readability (best during development). Minify removes all whitespace for production — reducing file transfer size significantly.
Common causes: trailing commas after the last item (JSON does not allow them unlike JavaScript), single quotes instead of double quotes, unquoted property keys, or missing brackets. The error message pinpoints the exact line.
Yes — there is no nesting depth limit. Complex APIs responses with multiple levels of objects and arrays validate correctly.
No — the tool validates standard JSON (RFC 8259). JSON5 and JSONC are supersets that add comments and relaxed syntax; they require dedicated parsers.
Yes — the tool handles large JSON payloads entirely in memory. Files up to several MB format without issues on modern browsers.
A minified API response looks like this:
{"user":{"id":1042,"name":"Aryan Singh","email":"aryan@example.com","roles":["admin","editor"],"prefs":{"theme":"dark","lang":"en"}}}
Formatted, it becomes immediately navigable:
{
"user": {
"id": 1042,
"name": "Aryan Singh",
"email": "aryan@example.com",
"roles": ["admin", "editor"],
"prefs": {
"theme": "dark",
"lang": "en"
}
}
}
Same data. Two minutes of reading time versus two seconds. That's what this tool does — plus syntax validation, error location, and minification in the other direction.
Format (Beautify): Takes any valid JSON string and outputs it with consistent 2-space indentation, line breaks, and visual structure. Uses JSON.parse() → JSON.stringify(parsed, null, 2).
Validate: If the input isn't valid JSON, the tool reports the error and, where possible, the character position where parsing failed. Helps you locate the exact problem in a 500-line response.
Minify: Removes all whitespace while preserving data integrity. Useful for reducing payload size in API requests, localStorage entries, or database storage. Uses JSON.stringify(JSON.parse(input)).
Syntax highlighting: Keys, values, strings, numbers, booleans, and null values are color-coded — making type mismatches (like "123" vs 123) immediately visible.
| Error | Invalid | Valid JSON |
|---|---|---|
| Trailing comma | {"a": 1,} | {"a": 1} |
| Single quotes | {'key': 'value'} | {"key": "value"} |
| Unquoted keys | {key: "value"} | {"key": "value"} |
| Missing comma | {"a": 1 "b": 2} | {"a": 1, "b": 2} |
| Comments | {"a": 1} // comment | (remove the comment) |
| Undefined value | {"a": undefined} | {"a": null} |
The validator catches all of these and shows the character offset where parsing stopped.
Debugging API responses: Copy the raw response body from your browser DevTools network tab, paste here. Structure becomes visible in seconds, eliminating the need to trace objects in your head.
Reading webhook payloads: Log an incoming webhook for debugging — the raw log line is always a compressed JSON blob. Paste and read.
Validating config files: JSON config files (settings.json, launch.json, etc.) often have subtle syntax errors. The validator catches these before...
Looking for a more detailed deep-dive and advanced tips?
Read Full Article on our BlogYour data never leaves this device. All processing is handled locally by JavaScript.