DevsToolkit

JSON Validator

JSON

Validate JSON syntax and get detailed error messages

All processing happens locally in your browser — your data never leaves your machine.
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Examples

Valid JSON

Input
{"name": "John", "age": 30}
Output
Valid JSON

Invalid - Trailing Comma

Input
{"name": "John", "age": 30,}
Output
Error: Unexpected token } at position 28

Invalid - Missing Quotes

Input
{name: "John"}
Output
Error: Unexpected token n at position 1

Frequently Asked Questions

What errors does the JSON Validator detect?
The validator detects all JSON syntax errors including missing commas, unclosed brackets, invalid escape sequences, trailing commas, and more. It provides the exact position where the error occurs.
Can I validate large JSON files?
Yes. Since validation runs locally in your browser, there's no upload limit. Performance depends on your device but typically handles files up to several megabytes without issues.

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