JSON Validator

Validate, format, and minify JSON — see parse errors with exact line/column.

Validator Web Dev Updated Apr 19, 2026
Learn how this works
How to Use
  1. Paste JSON on the left.
  2. Errors are reported with line and column.
  3. Use format / minify buttons to beautify or compact.
JSON input
Result

Common errors

Trailing comma
Not valid JSON ({"a": 1,})
Single quotes
JSON requires "double quotes"
Unquoted keys
{ a: 1 } — keys must be "quoted"
Comments
Strict JSON doesn\'t allow // or /* */
undefined
Not a JSON value — use null
NaN / Infinity
Not valid JSON numbers

About the JSON Validator

Need a hand with web development and data tasks? The JSON Validator does the work for you — free, and right here in your browser. Validate, format, and minify JSON — see parse errors with exact line/column.

How it works

Type in what you have, and the answer shows up right away. Change anything and it updates by itself. Everything runs in your browser, so it is fast and nothing you type is sent away.

Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.

Frequently Asked Questions

How do I use the JSON Validator?

Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.

Is it free? Does it work without internet?

Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.

Where does my data go?

Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.

Common Use Cases

Try different numbers

Change one thing and watch the answer change. It is an easy way to compare your choices.

Nothing to set up

Open the page and start. There is nothing to install, and no account to make.

Check your work

Worked it out yourself? Use the JSON Validator to make sure your answer is right.

Safe and private

Everything you type stays on your device. Nothing is sent to a server or saved.

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