Check copied payloads
Catch missing commas, quotes and brackets after copying JSON between tools or documents.
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JSON Syntax Validator
Validate JSON syntax online and get a clear parsing error. The JSON validator runs locally in your browser.
✓ Free to use✓ No signup✓ Runs locally
160 bytes · local only
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Processed entirely in this tab
Your input and result are not sent to JSON Hearth or stored on a server.
When to use it
What Validator helps you do
The syntax validator answers one focused question: can the supplied text be parsed as JSON? It is useful before sending, storing or committing a payload.
Validate configuration
Confirm that a JSON configuration file is syntactically readable before deployment.
Debug API errors
Separate JSON syntax failures from schema, authorization and business-rule errors.
Important limitations
What to check before using the result
- Syntax validity does not prove that the fields match an API or application contract.
- Use the JSON Schema validator when you need required fields, types or value constraints checked.
Common questions
About Validator
Is valid JSON automatically valid for my API?
No. A document can be valid JSON while still containing the wrong fields, types or values for a particular API.
Are comments allowed in JSON?
Standard JSON does not support comments. Formats such as JSONC are separate extensions.