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JSON Validator

Validate JSON syntax and pinpoint errors with clear messages.

JSON ToolsBrowser-only • PrivateFree

JSON Input

Validation Result

Output will appear here...

Privacy First: All processing happens locally in your browser. Your data never leaves your device and is never uploaded to any server.

About JSON Validator

The JSON Validator checks whether your JSON is syntactically correct and, when it isn't, reports the exact location and reason for the error. It catches the mistakes that break parsers — trailing commas, single quotes, unquoted keys, and unbalanced brackets — before they cause a runtime failure. Validation happens in your browser, so you can safely check private payloads. Once it's valid, format it with the JSON Formatter or check it against a schema with the JSON Schema Validator.

How to Use

1Open JSON Validator and paste or type your data into the input area.
2Adjust any available options to match the result you want.
3Your output is generated instantly — no button-clicking required for most tools.
4Use the Copy or Download button to save your result.

Common Use Cases

Debugging API responses while building web and mobile apps
Cleaning up minified or messy JSON from logs and network tabs
Preparing configuration files and fixtures for testing
Converting data between JSON and other formats for imports/exports

Frequently Asked Questions

What kinds of errors does the JSON validator catch?

It flags every syntax error the JSON spec forbids: trailing commas, single-quoted strings, unquoted object keys, missing commas or colons, and unbalanced braces or brackets — with the position of the first failure.

Does valid JSON mean my data is correct?

It means the syntax is correct. To also check that fields, types, and required properties match an expected shape, validate against a schema using the JSON Schema Validator.

Is JSON Validator free to use?

Yes. JSON Validator is completely free with no sign-up, no subscription, and no usage limits. Every tool on CodeUtilityKit is free forever.

Is my data safe when I use JSON Validator?

Absolutely. JSON Validator runs entirely in your browser. Your input is processed locally with JavaScript and is never sent to, stored on, or logged by any server — so it is safe even for private or sensitive data.