JSON Validator
JSON Validator
Paste JSON below to check it. Errors show the message and position when the browser reports one.
The JSON Validator checks whether your JSON follows the official rules and tells you exactly where it breaks when it does not. JSON powers APIs, app settings, and data files everywhere, yet it is unforgiving: one missing comma, one single quote, or one trailing comma and the whole file fails. Finding that one character by eye in a long file wastes real time.
Paste your data, click Validate, and you get a clear valid or invalid answer. When the JSON is valid, the tool also shows a neatly indented version so you can read the structure at a glance. When it is invalid, the browser error message is shown, including the position of the problem whenever the browser reports one, so you can jump straight to the faulty spot.
Everything runs in your browser. Your JSON is never uploaded, stored, or shared, which makes the validator safe for API responses, tokens in test data, and private configuration files.
How to use
- Paste or type your JSON into the box.
- Click Validate.
- If the result is valid, review or copy the pretty-printed output below.
- If it is invalid, read the error, fix the reported position in your text, and validate again.
- Use Load Sample if you want to see a working example first.
Frequently asked questions
Why is my JSON invalid?
The most common causes are single quotes instead of double quotes, missing commas between items, extra commas at the end of a list or object, unquoted keys, and comments, which JSON does not allow at all.
Does the error always give an exact position?
Most modern browsers include a position in the parse error and this tool shows it. If your browser reports only a general message, check the area the message describes and look for punctuation mistakes nearby.
Is my data sent to a server?
No. Validation uses the JSON parser built into your browser. Nothing leaves your device and refreshing the page clears everything.
Can I validate very large JSON?
Yes, within your device memory. Very large files may take a moment to pretty-print, but validation itself is fast because it uses the native browser parser.