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JSON Validator Tool

Validate, format, and analyze JSON data with detailed error reporting. Perfect for developers working with APIs, configurations, or any JSON data that needs syntax checking and beautification.

JSON Validator

Validate, format, and analyze JSON data with detailed error reporting and syntax checking

Validation Options:
JSON Input

Validation Results

Valid JSON Warnings Found Invalid JSON
JSON Size: 0
Character Count: 0
Line Count: 0
Object Depth: 0
Total Keys: 0
Array Count: 0
String Values: 0
Number Values: 0
Boolean Values: 0

Validation results will appear here after running the validator.

Advanced JSON Validation Features

Detailed Error Analysis

Get precise line numbers, column positions, and suggestions for fixing JSON errors.

Flexible Validation

Toggle between strict JSON mode or relaxed mode that allows comments and trailing commas.

Auto-Fix Issues

Automatically fix common JSON problems like trailing commas and single quotes.

Structure Visualization

Analyze JSON structure, depth, and data type distribution for better understanding.

Advanced JSON Validation Features

Enhanced Error Detection:

  • Precise Error Location - Exact line and column numbers for every error
  • Context-Aware Suggestions - Intelligent fix suggestions based on error type
  • Multiple Validation Modes - Switch between strict JSON and relaxed modes
  • Real-time Validation - Instant feedback as you type with debouncing
  • Batch Error Reporting - See all errors at once, not just the first one

Auto-Fix Capabilities:

  • Comment Removal - Strip JavaScript-style comments from JSON
  • Quote Conversion - Convert single quotes to double quotes automatically
  • Trailing Comma Fix - Remove or preserve trailing commas based on settings
  • Whitespace Normalization - Standardize spacing and indentation
  • Unicode Escaping - Properly escape special characters

Validation Modes:

  • Strict Mode - Follows official JSON specification (RFC 8259)
  • Relaxed Mode - Allows comments, trailing commas, and single quotes
  • JSON5 Mode - Supports extended JSON5 features
  • Custom Mode - Configure your own validation rules

JSON Validation FAQ

JSON was designed to be a data interchange format, not a configuration language. The creator of JSON, Douglas Crockford, intentionally excluded comments to keep the specification simple and to prevent people from using comments for parsing directives. However, many JSON parsers now support comments in practice. Our tool can handle both strict JSON and JSON with comments.

JSON5 is an extension of JSON that adds features commonly used in JavaScript object literals:
  • Comments (single-line and multi-line)
  • Trailing commas in objects and arrays
  • Single-quoted strings
  • Unquoted property names (when valid identifiers)
  • Hexadecimal numbers
  • Plus and minus signs as numbers
  • Numbers with leading or trailing decimal points
Our tool supports many JSON5 features when in relaxed mode.

Our error location reporting is highly accurate. We track line numbers and column positions during parsing and provide specific locations for:
  • Missing commas or brackets
  • Invalid string escape sequences
  • Number format errors
  • Unexpected tokens
  • Type mismatches
For complex errors, we provide context showing the surrounding text to help identify the issue.

No, JSON is a data-only format and cannot contain JavaScript code, function definitions, or expressions. If you need to validate JSON with embedded JavaScript, you're likely working with a JavaScript object literal, not JSON. Our tool will flag JavaScript code as invalid JSON. However, you can use the "Remove Comments" feature to strip JavaScript comments from your data.

The auto-fix feature uses pattern matching and context-aware transformations to fix common JSON issues:
  • Replaces single quotes with double quotes
  • Removes trailing commas from objects and arrays
  • Strips JavaScript-style comments
  • Fixes missing commas between object properties
  • Corrects common escape sequence errors
Each fix is logged so you can review what was changed. The original content is preserved until you accept the changes.

JSON Best Practices

Use Consistent Formatting

Maintain consistent indentation (2 or 4 spaces) for readability.

Validate Early & Often

Validate JSON during development, not just before deployment.

Choose the Right Mode

Use strict mode for APIs and relaxed mode for configuration files.

Keep It Simple

Avoid overly complex nested structures when possible.

Common JSON Errors

Missing Comma

{"a": 1 "b": 2} → {"a": 1, "b": 2}

Unclosed Bracket

{"a": [1, 2, 3} → {"a": [1, 2, 3]}

Single Quotes

{'a': 'value'} → {"a": "value"}

Trailing Comma

{"a": 1, "b": 2,} → {"a": 1, "b": 2}

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