The #1 Free JSON Tool

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Format, Repair, and Validate your JSON data instantly. The ultimate developer toolkit includes JSON Generator, Converter, Diff Checker, and Path Finder.

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JSON Tools and Validation Guide

What is JSON Format?

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that's easy for humans to read and write, and simple for machines to parse and generate. It has become the standard for web APIs and configuration files.

Objects: Collections of key-value pairs enclosed in curly braces { }
Arrays: Ordered lists of values enclosed in square brackets [ ]
          {
  "name": "John Doe",
  "age": 30,
  "skills": ["JavaScript", "Python"],
  "active": true
}
        

JSON Schema Validation

JSON Schema provides a contract for your JSON data, ensuring it meets specific requirements. It defines the structure, data types, required fields, and validation rules for your JSON documents.

Validate data structure and types automatically
Enforce required fields and constraints
Document your API contracts clearly
          {
  "type": "object",
  "properties": {
    "name": { "type": "string" },
    "age": { 
      "type": "integer",
      "minimum": 0,
      "maximum": 120
    }
  },
  "required": ["name"]
}
        

Common JSON Syntax Errors

Avoid these frequent mistakes that cause JSON parsing errors. Our validator helps you identify and fix these issues instantly.

Missing Quotes

Property names must be enclosed in double quotes

Trailing Commas

Remove commas after the last item in objects/arrays

Single Quotes

Use double quotes, not single quotes for strings

Incorrect

              {
  name: 'John',
  age: 30,
}
            

Correct

              {
  "name": "John",
  "age": 30
}
            

Why Use JSON Master?

Powerful, free tools to format, validate, and transform your JSON data. Save time and eliminate errors with our comprehensive JSON toolkit.

Format & Beautify

Transform messy JSON into readable, properly indented code instantly

Validate & Fix Errors

Detect syntax errors with precise line numbers and helpful suggestions

Convert Formats

Transform between JSON, CSV, XML, and YAML with one click

Query with JSON Path

Extract specific values from complex nested JSON structures easily

Discover Advanced JSON Tools

Powerful, free tools to format, validate, and transform JSON data efficiently

JSON Guides & Tutorials

Learn best practices, common errors, and optimization techniques

Common JSON Questions

Find answers to frequently asked questions

Our Other Tools

Explore more useful tools and platforms we built for developers

References & Useful Resources

Trusted documentation and resources for JSON standards and best practices.