About JSON Formatter
JSON Formatter pretty-prints, minifies, and validates a JSON document directly in your browser. Paste in raw JSON — for example, the body of an API response, a webhook payload, or a config file — and the tool reformats it with consistent indentation, sorts nothing, and surfaces the exact line and column where the parser failed if the input is invalid.
Formatted JSON is much easier to scan than a single-line response: nested objects line up, arrays break across lines, and trailing commas or missing brackets become obvious. When you are ready to ship the output to a network call, log line, or environment variable, the same tool minifies it back to the smallest valid representation in one click. Everything runs locally with the browser's native JSON parser, so the document you paste never leaves your device — useful when you are debugging payloads that contain access tokens or user data.
Examples
{"name":"Ada","born":1815,"contributions":["Note G",{"on":"Analytical Engine"}]}{
"name": "Ada",
"born": 1815,
"contributions": [
"Note G",
{
"on": "Analytical Engine"
}
]
}Pretty-print with 2-space indentation. Use the indent control to switch to 4 spaces or tabs.
{
"ok": true,
"items": [1, 2, 3]
}{"ok":true,"items":[1,2,3]}Minify mode strips every byte of insignificant whitespace, ideal for embedding JSON in a URL, header, or single log line.
Frequently asked questions
Is my JSON sent to a server?
No. JSON Formatter parses and re-serializes the document with the browser's built-in JSON.parse and JSON.stringify. Nothing is uploaded, logged, or stored on our side. You can verify this by opening your browser's network tab while running the tool — there is no outbound request for the input.
What happens when the JSON is invalid?
The tool reports the parser error message and the position (line and column) where parsing failed. Common causes are trailing commas after the last property of an object, single-quoted strings, unquoted keys, and stray comments — all of which are valid in JavaScript but not in strict JSON.
Does it preserve key order?
Yes. Pretty-printing and minification are both order-preserving — the tool emits keys in the same sequence as the input. If you need a stable, alphabetical order for diffing or hashing, use the JSON Sort Keys tool instead.
What is the difference between formatting and minifying?
Formatting (pretty-printing) inserts newlines and indentation so the structure is readable. Minifying removes every space, tab, and newline that is not inside a string, producing the smallest valid representation. Both produce semantically identical JSON; minified output is what you want over the network, formatted output is what you want in your editor.
Can it handle very large JSON files?
It can handle anything that fits comfortably in the browser tab, which on a modern desktop is hundreds of megabytes. For multi-gigabyte logs you are better off with a streaming command-line tool such as jq, since the browser must hold the whole document in memory at once.