How does this JSON formatter work?

This tool uses the browser's native JSON.parse and JSON.stringify functions. Paste JSON to format it with configurable indentation (2 spaces, 4 spaces, or a tab), minify it to a single line with no whitespace, or validate it. When JSON is invalid, errors are pinpointed by line and column number. Nothing is sent to any server.

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JSON Formatter & Validator.

Paste JSON in, get it formatted, minified, or validated. Syntax errors are pinpointed by line and column. Nothing leaves your browser, so it's safe for production payloads and tokens.

// paste JSON

// indent

// output

// how it works

This tool runs entirely in your browser using the native JSON.parse and JSON.stringify functions. No data is sent anywhere; you can verify by viewing the source of this page or checking your browser's network tab while you use it.

Because it's local, you can paste anything you'd otherwise be hesitant to drop into a web form: auth tokens, customer payloads, internal config, anything covered by an NDA or compliance requirement.

Error messages include line and column numbers. The browser's native parser only returns a byte offset; this tool translates that into a human-readable position you can jump to.

Use the Sample button to load a small valid example if you just want to try the formatter without hunting for JSON in a tab.

Related: need to minify JavaScript instead of JSON? The JavaScript Minifier handles JS the same browser-local way using Terser.

// a free, browser-only tool by Tiempo Software, built in Omaha, Nebraska. Runs entirely in your browser; nothing you enter is uploaded. see all tools.