Free JSON Validator & Formatter
Validate JSON syntax, format with custom indentation, minify for production, and analyze your JSON structure. Instant error detection with line numbers.
JSON Validator & Formatter
Formatted JSON will appear here...
Common JSON Errors
{"a": 1,} {'a': 'b'} {a: "b"} {"a": 1} // comment How to Use the JSON Validator & Formatter
Paste Your JSON Data
Copy your JSON content and paste it into the input area. You can also type JSON directly. The validator accepts any size JSON from small objects to large arrays.
Check Validation Status
The tool instantly validates your JSON as you type. Valid JSON shows a green checkmark. Invalid JSON shows the exact error location with line and column numbers.
Format or Minify
Click Format to prettify your JSON with proper indentation (2 or 4 spaces). Click Minify to remove all whitespace for smaller file size. Both preserve the data structure.
Copy or Download Results
Copy the formatted or minified JSON to your clipboard with one click. You can also view the structure analysis showing counts of objects, arrays, strings, and other data types.
Pro tip: Your data is processed entirely in your browser. Nothing is sent to any server, ensuring complete privacy.
About JSON Validation
JSON (JavaScript Object Notation) is the standard data interchange format for web APIs and configuration files. Valid JSON must follow strict syntax rules - our validator checks your JSON against the official specification and provides clear error messages when issues are found.
Features
- Real-time Validation: Instant syntax checking as you type
- Error Location: Pinpoints exact line and column of syntax errors
- Formatting Options: Pretty print with 2 or 4 space indentation
- Minification: Remove whitespace for smaller file sizes
- Structure Analysis: Count objects, arrays, and data types
- Size Comparison: See original vs formatted vs minified sizes
Frequently Asked Questions
What is JSON validation?
JSON validation checks whether a string conforms to the JSON (JavaScript Object Notation) specification. Valid JSON must have properly quoted strings, correct bracket matching, no trailing commas, and valid data types. Our validator instantly detects syntax errors and shows you exactly where they occur.
Why is my JSON invalid?
Common JSON errors include: trailing commas after the last item, single quotes instead of double quotes, unquoted property names, comments (JSON doesn't support comments), special characters not properly escaped, and missing brackets or braces. Our validator highlights the exact error location.
What is the difference between minified and formatted JSON?
Formatted (or "pretty printed") JSON includes indentation and line breaks for human readability. Minified JSON removes all unnecessary whitespace to reduce file size for transmission. Both are valid JSON - formatting only affects readability, not functionality.
How do I fix JSON syntax errors?
Look at the error message and position. Common fixes: replace single quotes with double quotes, remove trailing commas, add quotes around property names, escape special characters with backslash, and ensure all brackets/braces are properly matched.
What JSON data types are supported?
JSON supports six data types: strings (in double quotes), numbers (integer or floating point), booleans (true/false), null, objects (key-value pairs in curly braces), and arrays (ordered lists in square brackets). Our analyzer shows the count of each type in your JSON.
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