JSON Validation: How to Check if Your JSON is Valid

Invalid JSON can break your applications, cause API failures, and waste hours of debugging time. Learning how to validate JSON properly is an essential skill for every developer. Our free JSON Validator helps you check JSON instantly.

Why JSON Validation Matters

A single missing comma, extra trailing comma, or unquoted key can make an entire JSON document unparseable. JSON validation catches these errors before they reach production. Using a JSON Linter also helps enforce consistent formatting across your team.

How to Validate JSON Online

1. Paste your JSON into our JSON validator.
2. The tool instantly checks syntax and reports any errors.
3. Fix the highlighted issues and re-validate.

Common JSON Errors

• Trailing commas — JSON doesn't allow trailing commas after the last item
• Missing quotes — Object keys must be double-quoted
• Single quotes — JSON only supports double quotes for strings
• Comments — Standard JSON doesn't support comments (use JSONC to JSON to strip them)

Fixing Invalid JSON

Our JSON Repair tool can automatically fix common issues like trailing commas, missing quotes, and single quotes. For JSONC files with comments, use our dedicated JSONC to JSON converter.

Frequently Asked Questions

What makes JSON invalid?

Common causes include syntax errors (missing brackets, commas), encoding issues, truncation, and non-standard extensions like comments or single quotes.

Is JSON validation secure?

Yes. Our online JSON validator processes everything in your browser. No data is ever uploaded.

Use our free JSON validator to check your JSON now.