Free Online JSON Validator
Toolharo's JSON Validator helps you check whether your JSON data is correctly formatted, in seconds. Simply paste your JSON code into the box below, click "Validate JSON," and instantly see whether it's valid. If there's a mistake, we'll show you exactly where the error is, including the line number, so you can fix it quickly. It's completely free, works right in your browser, and doesn't require any signup or software installation.
How to Use the JSON Validator
- Paste your JSON data into the input box, or type it directly.
- Click the "Validate JSON" button.
- If your JSON is valid, you'll see a green success message.
- If there's an error, you'll see a red message describing the problem and the line number where it occurred, so you can fix it easily.
- Use "Format / Beautify" to automatically re-indent valid JSON for readability.
- Click "Copy" to copy the current content to your clipboard, or "Clear" to start over.
Frequently Asked Questions
Is this JSON Validator free to use?
Yes, Toolharo's JSON Validator is completely free, with no signup or download required.
Is my data uploaded to a server?
No. All validation happens directly in your browser using JavaScript, so your JSON data never leaves your computer.
What does "invalid JSON" mean?
It means your JSON text doesn't follow the correct syntax rules, such as a missing comma, an extra bracket, or unquoted keys. The validator points out the exact issue and line number so you can fix it.
Can I format messy JSON with this tool?
Yes. Once your JSON is valid, click "Format / Beautify" to automatically re-indent it for readability.
What is JSON used for?
JSON (JavaScript Object Notation) is a lightweight data format commonly used to exchange data between servers, APIs, and web applications.