Developer

JSON validator

Validate, format and minify JSON in your browser.

Output

How it works

1

Paste your JSON

Drop in JSON from an API response, a config file or anywhere else.

2

Format or minify

Pretty-print with clean indentation for reading, or minify to the smallest valid string.

3

Fix and copy

Errors point to the line and position so you can fix them, then copy the result.

Why use JSON validator

Clear error messages

Invalid JSON is flagged with the position of the problem, so you can find a stray comma or bracket fast.

Readable or compact

Switch between pretty-printed and minified output depending on whether you are debugging or shipping.

Stays on your device

Paste sensitive payloads without worry — nothing is uploaded or logged.

Frequent questions

Is my JSON sent to a server?
No. Validation, formatting and minifying all happen in your browser, so even sensitive data stays local.
Why does it say my JSON is invalid?
Common causes are trailing commas, single quotes instead of double quotes, or unquoted keys. The error points to where parsing failed so you can fix it.
What is the difference between formatting and minifying?
Formatting adds indentation and line breaks so JSON is easy to read; minifying strips all optional whitespace to make the smallest valid payload.