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JSON Formatter & Validator

Format, beautify, and validate your JSON data. Check for syntax errors and get clean, readable JSON structures.

Input JSON

Results

Status
Ready to process JSON

Formatted JSON

{
    "name": "John Doe",
    "age": 30,
    "email": "john@example.com",
    "address": {
        "city": "New York",
        "zip": 10001
    },
    "hobbies": [
        "reading",
        "coding"
    ]
}

How To Use JSON Formatter & Validator

📝 Step 1: Enter JSON Data

Paste your JSON in the input area. The tool accepts any valid JSON structure (objects, arrays, nested data).

⚙️ Step 2: Choose Action

Click "Format JSON" to beautify your code with proper indentation. Click "Validate JSON" to check for syntax errors according to RFC 8259.

🔧 Step 3: Adjust Indentation

Select 2 or 4 spaces for indentation to match your preferred coding style.

📋 Step 4: Copy or Download

Use the "Copy" button to copy formatted JSON to clipboard, or "Download" to save as .json file.

💡 Pro Tips

  • Use the Sample button to load an example JSON
  • Validation checks for: missing commas, trailing commas, unquoted keys, invalid data types
  • Formatting preserves data structure and escapes special characters
  • Works with large JSON files (tested up to 5MB)

🔍 Example

// Before formatting: {"users":[{"id":1,"name":"Alice","active":true},{"id":2,"name":"Bob","active":false}],"total":2} // After formatting (2 spaces): { "users": [ { "id": 1, "name": "Alice", "active": true }, { "id": 2, "name": "Bob", "active": false } ], "total": 2 }

Frequently Asked Questions

What JSON standards are supported? ▼
We validate against RFC 8259 (the official JSON specification). This includes support for strings, numbers, booleans, null, objects, and arrays. Keys must be double-quoted, and strings must use double quotes.
Does it validate all JSON syntax rules? ▼
The validator checks for common errors: missing commas, trailing commas, unquoted keys, invalid number formats, unescaped control characters, mismatched brackets/braces, and duplicate keys (warning). It ensures your JSON is structurally sound.
What formatting options are available? ▼
The formatter adds proper indentation (2 or 4 spaces), line breaks after each element, and consistent spacing. It preserves all data while making it human-readable. You can also choose to minify by copying without formatting.
Can I format large JSON files? ▼
Yes! All processing happens in your browser, so performance depends on your device. Files up to 5MB are handled smoothly. For extremely large files, formatting may take a few seconds.
Is my JSON data secure? ▼
Absolutely. All processing happens 100% client-side in your browser. Your JSON is never sent to our servers. You can verify this by checking the Network tab in Developer Tools.
What are common JSON errors it detects? ▼
Common errors include: missing quotes trailing commas unquoted keys invalid escape sequences mismatched brackets unexpected data types. It also warns about duplicate keys.
Does it work with JSONL (JSON Lines)? ▼
Yes, it supports JSON Lines format where each line is a separate JSON object. The tool will format each line independently and show validation errors per line.
How accurate is the validation? ▼
The validation is extremely accurate for syntax checking. It catches all errors defined in the JSON specification. However, it doesn't validate against custom schemas (use a JSON Schema validator for that). It's perfect for ensuring your JSON is well-formed.