JSON Formatter & Validator

Format, beautify and validate JSON data

Input JSON

Indent:

Formatted Output

What is JSON?

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that has become the de facto standard for transmitting data between servers and web applications. Originally derived from JavaScript, JSON is now language-independent and supported by virtually every modern programming language including Python, Java, C#, PHP, Ruby, and Go.

JSON's simplicity and human-readability make it superior to alternatives like XML for most use cases. It uses key-value pairs and arrays to structure data, making it intuitive for developers to read, write, and debug. This tool helps you format, validate, and beautify JSON data for easier analysis and development.

How to Use This Tool

Formatting JSON

Paste your JSON data into the "Input JSON" field
Select your preferred indentation (2 spaces, 4 spaces, or tabs)
Click "Format" to beautify the JSON with proper indentation
Copy the formatted output or download as a .json file

Minifying JSON

Paste your formatted JSON into the input field
Click "Minify" to remove all unnecessary whitespace
The result is compact JSON ideal for production use

Validating JSON

Paste your JSON into the input field
Click "Validate" to check if the JSON is syntactically correct
If invalid, you'll see the specific error and line number

Common Use Cases

🔧 API Response Debugging

When working with REST APIs, responses often come as minified JSON. Formatting makes it easy to read and understand the data structure, identify fields, and debug issues.

📝 Configuration Files

Many applications use JSON for configuration (package.json, tsconfig.json, etc.). Formatting ensures these files remain readable and maintainable while validating syntax before deployment.

📊 Database Export Analysis

MongoDB exports and other NoSQL databases often output JSON. Formatting helps analyze the data structure, verify integrity, and prepare data for import into other systems.

🚀 Production Optimization

Minifying JSON removes whitespace, reducing file size by 10-40%. This improves load times and reduces bandwidth usage for API responses and configuration files.

📋 Documentation & Sharing

When documenting APIs or sharing data structures with team members, formatted JSON with consistent indentation makes the content much clearer and more professional.

JSON Syntax Quick Reference

Valid Data Types

String: "hello"
Number: 42 or 3.14
Boolean: true or false
Null: null
Array: [1, 2, 3]
Object: {"key": "value"}

Common Syntax Errors

Trailing commas after last item
Single quotes instead of double quotes
Unquoted property names
Comments (not allowed in JSON)
Missing commas between items
Undefined values (use null instead)

Frequently Asked Questions

What's the difference between JSON and JavaScript objects?

While similar, JSON is stricter: keys must be double-quoted strings, no trailing commas, no comments, no undefined values, and no functions. JSON is a data format, while JavaScript objects are programming constructs.

Why is my JSON invalid?

Common causes include: trailing commas, single quotes instead of double quotes, unquoted keys, or missing commas between elements. Our validator will show you exactly where the error occurs.

Is my data secure when using this tool?

Yes! All processing happens entirely in your browser using JavaScript. Your JSON data never leaves your device and is never sent to any server. It's completely private and secure.

What indentation should I use?

2 spaces is most common for web development and keeps files compact. 4 spaces improves readability for complex structures. Tabs offer flexibility but may display differently across editors.

Can JSON contain comments?

No, standard JSON does not support comments. If you need comments, consider using JSONC (JSON with Comments) or JSON5, but note these are extensions and won't validate as standard JSON.

How do I handle large JSON files?

Our tool handles JSON up to several megabytes efficiently. For very large files (100MB+), consider using command-line tools like jq, or streaming JSON parsers to avoid memory issues.

Best Practices for Working with JSON

Always validate JSON before using it in production applications
Use consistent indentation (2 or 4 spaces) across your project
Minify JSON for production APIs to reduce bandwidth
Use descriptive, camelCase key names for readability
Keep JSON structures flat when possible to improve parsing performance
Consider using JSON Schema for complex data validation requirements
Store dates as ISO 8601 strings (e.g., "2024-01-15T10:30:00Z")
Use arrays for ordered lists and objects for key-value mappings