JSON Validator
Validate JSON payloads instantly in your browser to catch syntax errors.
Waiting for input
Paste your JSON below to validate.
Features
- Instant Validation: Feedback is provided as you type or paste your JSON payload.
- Detailed Error Messages: See exactly why your JSON is failing, including the location of the error when possible.
- 100% Client-Side: Your sensitive JSON data is processed entirely within your browser for maximum privacy and speed.
- Example Payloads: One-click buttons to load valid or invalid JSON to see how the validator reacts.
How it works
Simply paste your JSON string into the code editor. As you type, the validator runs continuously in the background using JavaScript's native JSON parser. If your syntax is perfect, you'll see a green "Valid JSON" banner. If there is a trailing comma, a missing quote, or an unescaped character, a red banner will appear showing the exact parser error.
Frequently Asked Questions
Everything you need to know about DevToolkit.
Why is my JSON failing validation?
The most common mistakes are: 1) Using single quotes instead of double quotes for keys or string values. 2) Leaving a trailing comma after the last item in an object or array. 3) Forgetting to escape special characters inside strings.
Do you save my JSON data?
No. This tool is fully static and runs locally in your browser. We don't have a backend database to save your data to, ensuring complete privacy.
Is there a size limit for validation?
No hard limit. Since validation happens on your device, it depends on your device's memory. Most modern browsers can handle files up to 50MB effortlessly.