JSON Formatter & Validator

Pretty-print, minify, and validate JSON locally with instant error pointers.

Great for API payloads and logs: nothing is sent to a server, and line/column hints speed up fixes.

Other languages: ja | en

Why use this formatter?

Validate fast

Format and debug JSON

Paste JSON, pick an indent, and format or minify. Errors are highlighted automatically with a caret under the position.

Parsing runs locally. Empty input stays empty without errors.

Formatted JSON

Preview

Frequently asked questions

Will my JSON be uploaded?

No. Parsing, formatting, and error highlighting happen only in your browser, so sample payloads stay on your device.

How are errors highlighted?

When parsing fails, the tool shows the line and column plus a caret under the exact position so you can fix it quickly.