Format, validate, and minify JSON data directly in your browser. Paste any JSON string and make it readable in one click.
JSON (JavaScript Object Notation) is a lightweight data-interchange format used extensively in web APIs, configuration files, and data storage. It's human-readable but can become difficult to parse when minified into a single line.
JSON documents are built from just a few building blocks: objects (curly braces { }), arrays (square brackets [ ]), strings, numbers, booleans, and null. Getting the syntax right is essential, which is why a validator that pinpoints errors is so useful.
Format: Transforms minified or poorly-formatted JSON into a clean, 2-space indented structure for easy reading and debugging.
Minify:Compresses formatted JSON into a single line — ideal for reducing file size in production environments.
Validation: Automatically detects and reports syntax errors in your JSON, with detailed error messages that point to the exact problem.
Pro tip: Press Cmd+Enter (Mac) or Ctrl+Enter (Windows) to format instantly.
Before (minified):
{"name":"Toolbox","tools":[{"name":"JSON Formatter","free":true},{"name":"Calculator","free":true}],"maintainer":"Community"}After (formatted):
{
"name": "Toolbox",
"tools": [
{
"name": "JSON Formatter",
"free": true
},
{
"name": "Calculator",
"free": true
}
],
"maintainer": "Community"
}Why is my JSON rejected as invalid?
The most common causes are trailing commas after the last item, single quotes instead of double quotes, unquoted keys, and comments. JSON strictly requires double-quoted strings and does not allow trailing commas or // comments.
Does it handle large or nested JSON?
Yes. Deeply nested objects and large arrays are supported. Formatting is performed in your browser, so very large documents are processed locally without uploading anything.
What is the difference between format and minify?
Format adds indentation and line breaks so the structure is easy to read. Minify removes all unnecessary whitespace and newlines to produce the smallest possible string for storage or transmission.
Can it format non-JSON like YAML or SQL?
No. This tool validates and formats JSON only. If your input is not valid JSON, it will be reported as an error rather than silently producing misleading output.
Is my data uploaded anywhere?
No. Everything is processed locally in your browser. You can safely paste confidential API responses or configuration files without worrying about them leaving your device.
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