Quick Tip: Common errors: Missing quotes around keys, trailing commas, or unescaped characters in strings.

JSON Input

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Paste JSON or drop a file to begin

Validation Report

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Quick Tips

• Strings must be in double quotes.
• No trailing commas in arrays/objects.
• All keys must be double-quoted.

What's Next?

JSON Indenter

Format your validated JSON

JSON Minifier

Compress valid JSON for production

JSON to Schema

Generate validation schema

Documentation

Learn JSON syntax rules

JSON Diff

Compare two JSON objects

5 Common JSON Errors

Avoid these mistakes

JSON Validator Guide

Validation best practices

Online JSON Validator

Validate JSON & JSON-LD Online

Our JSON Validator ensures your data complies perfectly with JSON standards (RFC 8259). It catches the most common developer mistakes instantly, acting as a high-performance JSON lint tool for professional workflows.

Missing Quotes: Identifies unquoted or single-quoted keys.
Trailing Commas: Flags commas at the end of objects or arrays.
Structural Integrity: Checks for mismatched braces and brackets.

What is JSON Lint?

JSON Lint is the process of analyzing JSON code for syntax errors and structural issues. Using a JSON Linter helps developers find bugs early, ensuring that data can be correctly parsed by web servers and applications without crashing.

How to Validate JSON Online

To validate JSON, paste your code into our syntax checker. It will perform a deep scan of the structure and highlight exact line numbers where errors occur. This makes it the fastest way to check JSON and ensure it is ready for production. You can easily validate json string online with our real-time feedback system.

Common JSON Errors

Why JSON Fails

JSON is a strict format. Even a single misplaced character can make the entire document invalid. Understanding these common pitfalls helps you write cleaner data schemas and debug API issues faster.

Most validation errors fall into these categories:

Syntax Violations: Broken braces, brackets, or missing commas.
Quote Mismatches: Using single quotes instead of double quotes.
Key Errors: Unquoted keys or reserved word conflicts.
Value Types: Incorrectly formatted numbers or booleans.

Trailing Commas

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

Standard JSON does not allow trailing commas in objects or arrays.

Unquoted Keys

{
  name: "John"  ← Invalid
}

All keys must be wrapped in double quotes.

Single Quotes

{
  "name": 'John'  ← Invalid
}

JSON syntax strictly requires double quotes for strings and keys.

Missing Commas

{
  "name": "John"
  "age": 30  ← Invalid
}

Object members must be separated by commas.

JSON Validation Examples

Valid JSON Examples

✅ Standard Object

{
  "name": "Alice",
  "age": 28,
  "active": true,
  "score": null
}

✅ Array of Objects

[
  { "id": 1, "val": "A" },
  { "id": 2, "val": "B" }
]

Common Error Output Patterns

❌ Trailing Comma

{
  "name": "Charlie",
  "age": 35,
}

Error: Unexpected token } in JSON at position 35

❌ Unquoted Key

{
  name: "Diana"
}

Error: Expected " but found n at position 4

❌ Single Quote

{
  "name": 'Eve'
}

Error: Unexpected token ' at position 11

❌ Number Format

{
  "price": .99
}

Error: Unexpected token . at position 12

Frequently Asked Questions

Is my data safe with this JSON tool?

Yes. This tool uses 100% client-side processing. Your JSON data never leaves your browser and is never sent to our servers, ensuring maximum privacy and security.

What constitutes 'valid' JSON?

Valid JSON follows RFC 8259. This includes double-quoted keys, no trailing commas, and specific formatting for strings, numbers, booleans, and null values.

Can I validate JSON-LD structured data with this tool?

Absolutely. Our validator is fully compatible with JSON-LD (JSON for Linked Data). It ensures your schema markup is syntactically correct, which is essential for SEO and Google Search visibility.