JSON Validator

Checks JSON syntax only, using the browser's own JSON.parse. For structural checks against a schema, see the JSON Schema Validator.

Private by architecture: All processing is 100% client-side memory. Your data never leaves this browser tab.

JSON input

0 lines · 0 charsJSON

Validation status

Paste JSON and click Validate.

Example

Invalid JSON with a trailing comma:

{
  "a": 1,
}

reports the exact line and column of the syntax error where the JSON engine provides one.

Is this the same as schema validation?: No. This only checks that the text is syntactically valid JSON. Use the JSON Schema Validator to check structure, types, and required fields.
Does it detect duplicate keys?: No. JSON.parse silently resolves duplicate keys to the last one before this tool ever sees the parsed value, so duplicate-key detection is not claimed.
Is my JSON logged anywhere?: No. Validation runs with plain JavaScript in your browser tab. Nothing is uploaded or logged.