JSON Formatter
How to Use the JSON Formatter
Step 1: Paste Your JSON
Copy your JSON data from any source and paste it into the input field above. You can also click "Load Sample" to see an example.
Step 2: Format or Validate
Click "Format / Beautify" to pretty-print your JSON with proper indentation, or click "Validate" to check for syntax errors.
Step 3: Copy the Result
Once formatted, click "Copy" to copy the beautified JSON to your clipboard. You can also choose between 2 spaces, 4 spaces, or tabs for indentation.
JSON Examples
Simple Object
{
"name": "John",
"age": 30,
"active": true
}
Array of Objects
[
{"id": 1, "name": "Item 1"},
{"id": 2, "name": "Item 2"}
]
Nested Structure
{
"user": {
"profile": {
"name": "Jane"
}
}
}
Common JSON Errors
Trailing Commas
JSON doesn't allow trailing commas after the last item in arrays or objects. Remove the comma before ] or }.
Single Quotes
JSON requires double quotes for strings. Use "text" not 'text'.
Unquoted Keys
Object keys must be quoted. Use {"key": value} not {key: value}.
Comments
JSON doesn't support comments. Remove any // or /* */ comments from your JSON.
Frequently Asked Questions
What is JSON and why do I need to format it?
JSON (JavaScript Object Notation) is a lightweight data format used for data exchange between servers and web applications. Formatting JSON makes it human-readable by adding proper indentation and line breaks, making it easier to debug and understand complex data structures.
Is my JSON data secure when using this tool?
Yes, absolutely. All JSON formatting and validation happens directly in your browser using JavaScript. Your data never leaves your device or gets sent to any server, ensuring complete privacy and security.
What are the most common JSON syntax errors?
The most common JSON errors include trailing commas after the last element, using single quotes instead of double quotes, unquoted property names, and including JavaScript comments. Our validator highlights these issues and shows you exactly where to fix them.
Can I minify JSON with this tool?
Yes! Our tool offers both beautification (pretty printing with indentation) and minification (removing all whitespace). Minified JSON is smaller in size, which is ideal for production use and API responses.
How to Use This Tool
- Paste Your JSON Data: Copy your JSON from any source—API responses, configuration files, or database exports—and paste it into the input textarea. The tool accepts any valid JSON structure including objects, arrays, and primitive values.
- Choose Your Operation: Click "Format / Beautify" to add proper indentation and line breaks for readability. Use "Minify" to remove all whitespace for production use. Click "Validate" to check syntax without modifying the output.
- Configure Indentation: Select 2 spaces, 4 spaces, or tabs from the dropdown based on your project's code style guidelines. The setting applies to all subsequent format operations.
- Copy the Result: Once formatted, click "Copy" to copy the output to your clipboard. The status indicator shows whether your JSON is valid, and error messages pinpoint the exact location of syntax problems.
Technical Details
This tool implements strict JSON parsing according to RFC 8259 (The JavaScript Object Notation Data Interchange Format). Valid JSON requires double-quoted strings for both keys and string values—single quotes are not permitted. Object keys must be unique within their scope, trailing commas after the last element are forbidden, and the only valid literals are true, false, and null (case-sensitive, lowercase).
Numbers follow IEEE 754 double-precision format: integers, decimals, and scientific notation (e.g., 1e10) are valid, but leading zeros, NaN, Infinity, and hexadecimal notation are not. The parser performs recursive descent validation, detecting errors at the exact character position. For large documents exceeding 1MB, consider streaming parsers in production code rather than loading the entire structure into memory.
Common Mistakes to Avoid
- Trailing Commas: JavaScript allows trailing commas in arrays and objects, but JSON does not. Remove the comma after the last element:
{"a": 1, "b": 2}not{"a": 1, "b": 2,}. - Single Quotes: JSON requires double quotes exclusively. Replace
'value'with"value". This applies to both property names and string values. - Unquoted Property Names: Unlike JavaScript objects, JSON requires all keys to be quoted strings. Use
{"name": "value"}not{name: "value"}.
Related Tools
Working with XML instead? Use our XML Formatter for similar formatting and validation. To convert between data formats, try the YAML/JSON Converter or CSV/JSON Converter.
Frequently Asked Questions
What is JSON and why do I need to format it?
JSON (JavaScript Object Notation) is a lightweight data format used for data exchange between servers and web applications. Formatting JSON makes it human-readable by adding proper indentation and line breaks, making it easier to debug and understand complex data structures.
Is my JSON data secure when using this tool?
Yes, absolutely. All JSON formatting and validation happens directly in your browser using JavaScript. Your data never leaves your device or gets sent to any server, ensuring complete privacy and security.
What are the most common JSON syntax errors?
The most common JSON errors include trailing commas after the last element, using single quotes instead of double quotes, unquoted property names, and including JavaScript comments. Our validator highlights these issues and shows you exactly where to fix them.
Can I minify JSON with this tool?
Yes! Our tool offers both beautification (pretty printing with indentation) and minification (removing all whitespace). Minified JSON is smaller in size, which is ideal for production use and API responses.