How does it detect JSON errors?

It calls the browser's built-in JSON.parse() on your input. If parsing fails, the native JavaScript error message is displayed — for example 'Unexpected token } at position 42' — which tells you exactly where the problem is.

What indentation style does Format use?

Format uses 2-space indentation via JSON.stringify(parsed, null, 2), which is the most common convention in JavaScript and TypeScript projects.

Can I format JSON with comments (JSONC)?

No. Standard JSON does not allow comments. If your input contains // or /* */ comments, JSON.parse will throw a syntax error. Strip comments before pasting.

Is there a file size limit?

No hard limit, but JSON inputs above ~5 MB may cause a brief freeze while the browser parses and stringifies the data. For very large files, a desktop tool like jq is more appropriate.

Is my JSON data sent to a server?

No. The formatter runs entirely in your browser using JavaScript. Your data never leaves your device, making it safe for API keys, tokens, and private config files.

JSON Formatter

Format, validate, and minify JSON data instantly.

How to use this tool

1Paste your raw or minified JSON into the left 'Input JSON' textarea.
2Click Format to pretty-print with 2-space indentation, or Minify to compact it into a single line.
3If the JSON is invalid, a red error message appears below the buttons describing the syntax problem.
4Copy the result from the right 'Output' textarea.

About JSON Formatter

Minified API responses are nearly impossible to read, and a single misplaced comma can silently break a config file. This JSON Formatter uses the browser's native JSON.parse() to validate your input first — if there's a syntax error, the exact error message from the JavaScript engine is shown in red below the editor so you know precisely what went wrong. On valid JSON, clicking Format produces a 2-space-indented pretty-print in the output panel; clicking Minify strips all whitespace to produce the most compact representation for reducing HTTP payload size. Both panels are editable textareas, so you can paste into either side. Common use cases include debugging REST API responses from tools like Postman or curl, formatting package.json or tsconfig.json before committing, and compressing JSON config before embedding it in an environment variable. Nothing is sent to any server — the entire parse-and-stringify cycle runs in your browser tab.

Frequently asked questions

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