📋 JSON Formatter & Validator

Format, validate, and compress JSON with smart mode detection.

Input
Output
Your formatted JSON will appear here...
0 chars · 0 lines · Press Ctrl+Enter to process

What Is JSON Formatting?

JSON (JavaScript Object Notation) is a lightweight data interchange format. Formatting makes JSON human-readable by adding proper indentation and line breaks. Validation checks that your JSON follows the correct syntax rules. Our tool handles both tasks in one click.

How to Use

Paste your raw JSON string into the input area. Select "Beautify" for pretty-printed output with 2-space indentation, or "Compress" for a minified single-line version. Click "Process JSON" — the tool validates the syntax first, then formats. Error messages help you fix invalid JSON quickly.

Usage Example

Input (minified):

{"name":"Alice","age":30,"city":"New York","skills":["Python","JavaScript","SQL"]}

Output (beautified):

{
  "name": "Alice",
  "age": 30,
  "city": "New York",
  "skills": [
    "Python",
    "JavaScript",
    "SQL"
  ]
}

Common JSON Errors

ErrorCauseFix
Unexpected tokenTrailing commaRemove the last comma before closing brace
Expected property nameSingle quotes instead of doubleReplace ' with " around property names
Unexpected numberLeading zerosRemove leading zeros (e.g., 01 → 1)

Frequently Asked Questions

Does it validate JSON Schema?

This tool validates JSON syntax only. For schema validation (checking that data matches a specific structure), you need a JSON Schema validator — a different tool entirely.

Is there a file size limit?

Since processing is local, the limit depends on your browser's memory. Most modern browsers handle JSON files up to 100MB without issues. The output size is displayed after processing.