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Online JSON Formatter and Minifier

Format, validate, and minify JSON with clear, instant error messages if something's wrong.

Runs entirely in your browser — your files are never uploaded to a server.

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This tool runs entirely in your browser. Your JSON data is never uploaded to our servers.

How It Works

1. Choose Your File

Drag & drop or select the file you want to work with.

2. Processed in Your Browser

Everything happens locally on your device — your file is never uploaded anywhere.

3. Download Your Result

Get your finished file instantly, ready to save or share.

About Online JSON Formatter and Minifier

Minified JSON from an API response or config file is genuinely hard to read as one long unbroken line. This tool adds consistent indentation and line breaks, turning unreadable output into something you can actually scan.

Beyond formatting, this doubles as a first line of defense against malformed JSON — if your JSON has a syntax error, formatting fails and points roughly where. For more detail on exactly what’s wrong, our JSON Validator reports the specific line and issue.

Everything happens in your browser — JSON pasted here often contains real data (API keys, internal URLs) that shouldn’t touch a third-party server even briefly.

Frequently Asked Questions

How to format a JSON file?

Open the file in a text editor, copy the contents and paste them into the box above. Click Format & Validate, then copy the indented result back into your file. The tool works on pasted text only, so there is no file upload button.

What indentation does the formatter use?

Formatted output uses two spaces per level. The indent size cannot be changed, and there is no key sorting or collapsible tree view. If you need the opposite, the Minify button strips whitespace so the JSON fits on a single line.

Will it fix broken JSON?

No. It parses your input strictly and, if the JSON is invalid, shows the parser's error message instead of output. Typical causes are trailing commas, single quotes or unquoted keys. Correct those in your source, then format again.

Is my JSON sent to a server?

No. Parsing and formatting happen in your browser using its built-in JSON functions, so your data is not uploaded by this tool. That makes it reasonable for configuration snippets, though you should still avoid pasting secrets into any web page.

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