JSON Validator Online

Validate JSON, understand syntax errors, preview safe repairs and check a local JSON Schema without uploading your data.

Your JSON and schema stay in this browser.

How this validator helps

Find the actual issue

Read a location-aware syntax message, duplicate-key warning or interoperability note.

Review repairs first

Common copy-and-paste fixes stay in a preview until you choose to use them.

Check a local schema

Use a simple inline JSON Schema; remote $ref values are never loaded.

When to use a JSON validator

Check an API response

Paste a copied response or configuration before sending, saving or sharing it. The diagnostic points to syntax problems without uploading the text.

Review hand-edited or AI-generated JSON

Preview a limited repair, then decide whether to use it. The original input is not replaced automatically.

Test a local contract

Check valid JSON against a simple inline JSON Schema while you work. Remote $ref values are not fetched.

Syntax validation and schema checks

Syntax validation checks whether text follows JSON grammar. A JSON Schema adds separate shape rules such as required fields and value types; this tool checks only the inline schema you provide and never loads remote references.

FAQ

JSON Validator FAQ

Is it safe to paste JSON into an online validator?

Yes, when the validator runs in your browser. This tool processes JSON locally; you can confirm that no JSON is sent out in your browser's Network panel.

How do I fix trailing comma errors in JSON?

Remove the comma after the final item in an object or array, or use the safe repair preview to review an automatic fix.

Can I validate JSON generated by AI / LLM?

Yes. Paste the AI output to catch common issues such as code fences, trailing commas and unquoted keys.

Does it support JSON Schema validation?

Yes. You can check JSON against local JSON Schema rules in this browser.

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