JSON Validator
Validate JSON syntax to ensure your JSON data is correctly formatted. This tool checks for syntax errors, missing commas, unclosed brackets, and other common JSON formatting issues. Get detailed error messages with line numbers to help you fix problems quickly.
When to use this tool
Your JSON parser is failing and you need a clear error location.
You are validating API payloads before sending or storing them.
Examples
Trailing comma issue
Input
{
"name": "jsonyaml",
"active": true,
}
Output
Error on line 4: Trailing comma is not allowed in JSON.
Remove the last comma before the closing brace.
Developer use cases
Verify webhook payloads before replaying them in staging.
Debug a config file that was manually edited or minified.
Common mistakes to avoid
Trailing commas after the last key or array item.
Unquoted keys or single quotes instead of double quotes.
Format and behavior notes
JSON requires double quotes for strings and keys.
Only these value types are allowed: string, number, object, array, boolean, null.
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Frequently Asked Questions
What does the JSON validator check?
The validator checks for proper JSON syntax including correct bracket matching, comma placement, proper string escaping, and valid data types.
How do I fix JSON errors?
The validator shows error messages with line numbers. Look for the highlighted error in the editor and fix the syntax issue indicated in the error message.
Does this validate JSON schema?
This tool validates JSON syntax only, not JSON schema. It ensures your JSON is properly formatted, not that it matches a specific schema structure.