Text & Dev

JSON Formatter & Validator

Paste messy JSON and get it back readable and validated, or minified for production. Errors are reported with the exact position.

How to json formatter & validator

  1. 1

    Add your file

    Drop your file into the box above or click to browse. It's processed privately in your browser — nothing is uploaded.

  2. 2

    Choose your options

    Adjust the available settings to get exactly the result you need.

  3. 3

    Download the result

    Run the tool and download your file instantly — no sign-up, no watermark.

About JSON Formatter & Validator

JSON arrives unformatted more often than not. An API returns a single 40-kilobyte line, a log entry is copied out of a terminal, or a config file has been edited by three people with different editors. A formatter turns that into something you can actually read, with consistent indentation and one value per line.

Validation is the other half of the job. Most JSON problems are small — a trailing comma after the last array element, single quotes instead of double, a key that was never quoted at all — and they are almost impossible to spot by eye in a wall of text. Here the parser tells you the position of the problem so you can go straight to it.

The minify option does the reverse for shipping: same data, no whitespace, smaller payload. And because everything runs in your browser, you can paste a production API response containing customer records or access tokens without it ever leaving your machine — which is not true of most online JSON formatters.

Frequently asked questions

How do I know my JSON is valid?+

If it parses, you get a formatted result and a "valid JSON" marker. If it does not, you get the browser's own parser error naming the character position where it went wrong, which is usually a trailing comma or an unquoted key.

What does minifying do?+

It removes every space and line break that is not inside a string. The data is identical but the payload is smaller, which is what you want in an API response or a config shipped to browsers.

Why sort the keys?+

Sorting keys alphabetically makes two versions of the same object directly comparable, which turns a messy diff into a readable one. It does not change the meaning — JSON objects are unordered by definition.

Can it handle large files?+

Yes, within your browser's memory. Formatting runs locally, so multi-megabyte documents are handled without any upload.

Does it support JSON with comments or trailing commas?+

No. Those are JSON5 or JSONC extensions, not valid JSON, so the parser rejects them — which is the honest answer, since most tools that consume your file will reject them too.

Is my data sent anywhere?+

Never. API responses, tokens and config files are parsed in this tab and nothing is transmitted or stored.

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