JSON Validator

What is the Free JSON Validator?

The free JSON Validator checks whether any text is valid JSON and gives you a precise error message the moment it finds a problem. Paste your JSON into the input textarea and the validator instantly reports a Valid ✓ or Invalid ✗ status, shows a structural breakdown (object count, array count, nesting depth), and highlights the exact character position of any parse error. Perfect for debugging API payloads, config files, and data feeds.

• → Verify API request and response bodies before sending to production
• → Check config files like appsettings.json or firebase.json for syntax errors
• → Validate JSON exported from spreadsheets, databases, or CMS platforms
• → Debug "Unexpected token" or "SyntaxError" messages thrown by your application
• → Inspect the structure of a deeply-nested JSON document at a glance

How to Use the Free JSON Validator

1. 1 Paste or type your JSON into the large input textarea.
2. 2 The Valid ✓ / Invalid ✗ badge at the top of the input updates instantly as you type.
3. 3 If the JSON is invalid, a red error message appears showing the exact parse problem — for example, "Unexpected token } at position 42".
4. 4 If valid, read the structure stats below — total count of objects, arrays, string keys, numbers, booleans, and the maximum nesting depth.
5. 5 Fix any issues directly in the textarea and watch the badge flip to green Valid ✓.

Key Features

• ⚡
  Live validation

  The Valid/Invalid status updates on every keystroke — no submit button needed.
• 🔍
  Precise error positions

  Errors include the exact character position so you can jump straight to the problem.
• 📊
  Structure breakdown

  See the total count of objects, arrays, keys, strings, numbers, booleans, and nesting depth.
• 🆓
  No size limits

  Validate JSON of any size with no rate limits or file size caps.
• 🔒
  100% private

  Your JSON never leaves your browser — ideal for sensitive configs and credentials.

Example Usage

{"user": {"id": 1, "name": "Alice", "roles": ["admin"]}}

✓ Valid JSON

Objects: 2  Arrays: 1  Keys: 3  Numbers: 1  Strings: 2  Max depth: 3

Frequently Asked Questions about the Free JSON Validator

What is the free JSON Validator?

Validate JSON syntax and get clear error messages for invalid JSON.

Is the JSON Validator free to use?

Yes, the JSON Validator is completely free. No account, subscription, or signup is required — ever.

Does my data get uploaded anywhere?

No. The JSON Validator runs entirely in your browser. Your data is never sent to any server.

Does it work offline?

Yes. Once the page has loaded, the tool works without an internet connection.

Which browsers are supported?

All modern browsers — Chrome, Firefox, Safari, and Edge. No plugins or extensions required.

What is the difference between JSON Validator and JSON Formatter?

The JSON Validator focuses on correctness — it tells you whether your JSON is valid and exactly where any errors are. The JSON Formatter assumes valid JSON and focuses on presentation — indenting, minifying, and syntax highlighting the output. Use the Validator to find and fix errors, then the Formatter to clean up the result.

Why does my JSON show as invalid when it looks correct?

The most common causes are: trailing commas after the last item in an object or array (not allowed in standard JSON), single-quoted strings (JSON requires double quotes), unquoted property names, or comments (// and /* */ are not valid in JSON). The error message points you to the exact character causing the issue.

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