How do I validate JSON online quickly?

Paste the JSON source into the editor and click Validate JSON. The tool checks whether the JSON is syntactically valid and shows the line and position where the parser fails if there is an error.

Does this JSON validator show line numbers?

Yes. The editor displays line numbers and highlights the likely error line when JSON parsing fails, so you can inspect the nearby comma, quote, brace, or extra text.

Can I use this as a JSON syntax checker for API responses?

Yes. Paste an API request, response body, webhook sample, or config file to check JSON syntax before formatting it or validating it against a schema.

Can I use this as a JavaScript JSON validator?

Yes. This page helps when JavaScript-style object snippets fail strict JSON parsing. It highlights issues like unquoted keys and single quotes so you can convert the snippet into valid JSON.

What makes JSON invalid?

Common issues include trailing commas, single quotes, unquoted keys, comments (JSON doesn't support comments), and mismatched brackets or braces. Unquoted keys are valid in JavaScript object literals and JSON5, but not in standard JSON.

How is this different from JSON Formatter?

JSON Validator only checks if your JSON is syntactically correct and tells you where errors are. JSON Formatter also beautifies valid JSON with indentation. Use Validator for quick checks, Formatter for cleanup.

Can I validate JSON Schema?

Use our JSON Schema Validator when you need to validate structure, required fields, and value rules against a schema. This tool checks syntax only.

Is my data sent to a server?

No. Validation happens entirely in your browser. Your data stays on your device.

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Validate JSON Online | JSON Validator with Line Numbers

Use this JSON validator online to check JSON syntax with line and position errors.

Paste JSON

1 line • 0 chars

Paste any JSON payload, API response, or config snippet to validate the syntax before formatting or schema checks.

Quick examples