JSON Validator

Runs entirely in your browser

Check your JSON for syntax errors directly in your browser. Get an exact error location, or a structural summary when it's valid.

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— Status
— Root type
— Keys / items
— Depth
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How to use JSON Validator

  1. Paste your JSON into the Input box.
  2. Click Validate.
  3. Fix the reported error, or review the structure summary and pretty preview for valid JSON.

Features

  • Clear valid/invalid status with exact error location.
  • Root type, key/item count and nesting depth for valid JSON.
  • Pretty-printed preview of valid JSON.
  • 100% client-side — your data never leaves your browser.

Example

Valid input:

{"user":{"name":"Ada","active":true}}

Validate reports Status: Valid, Root type: Object, Keys: 1, Depth: 2, and shows this pretty preview:

{
  "user": {
    "name": "Ada",
    "active": true
  }
}

Invalid input with a trailing comma:

{"name": "Toolbeel",}

reports: Invalid JSON — Expected double-quoted property name in JSON (line 1, column 21).

Tips

  • An unquoted object key, like {name: "Toolbeel"}, reports "Expected property name or '}' in JSON" — every key in JSON must be wrapped in double quotes, unlike a JavaScript object literal.
  • A trailing comma before } or ] is one of the most common errors — JSON doesn't allow a comma after the last item the way JavaScript does.
  • Depth counts nesting levels: an empty object or array counts as depth 1, and a plain string, number, boolean or null at the root counts as depth 0.
  • The exact wording of an error message depends on your browser's JavaScript engine — Chrome, Firefox and Safari phrase the same syntax error slightly differently, though the line/column detail is added consistently by this tool.

Is JSON Validator safe?

Yes. JSON Validator checks your JSON with your browser's own JavaScript engine, entirely on your device — the line and column in any error message come straight from that local parser, so nothing you paste is ever sent to a server.

Frequently Asked Questions

How do I find the exact error in my JSON?

When your JSON is invalid, the error message includes the line and column where the problem was found, when your browser provides that information.

What information do I get for valid JSON?

You'll see the root data type, the number of keys or items, the nesting depth, and a pretty-printed preview of your JSON.

Does this tool format my JSON too?

Valid JSON is shown pretty-printed in the Output box so you can review its structure, but for dedicated Beautify and Minify controls, use the JSON Formatter tool.

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