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JSON Formatter

JSON

Format, validate, and minify JSON

This is the tool most people land on first: paste JSON in any state (minified, hand-edited, or copied out of a log line) and get it pretty-printed with a specific syntax error location when it's broken, rather than a generic parser exception. It runs the browser's native JSON parser locally, so nothing you paste is uploaded, which matters if the payload includes real user data. It only understands strict JSON per RFC 8259; if your input has comments or trailing commas because it came from a hand-written config, reach for JSON Repair instead, since this tool will just reject it. For the opposite direction, stripping whitespace instead of adding it, JSON Minifier is the more purpose-built option, though this tool's minify mode covers the basic case too.

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How to use JSON Formatter

  • 1.Paste minified or messy JSON into the input box to get pretty-printed, indented output instantly.
  • 2.Use the minify mode to strip whitespace before sending a payload over the wire or embedding it in a config file.
  • 3.Paste invalid JSON to see exactly where the syntax error is (missing comma, unquoted key, trailing comma) instead of a vague parser error.

Frequently asked questions

Is my JSON data sent to a server?
No. Formatting and validation run entirely in your browser using the built-in JSON parser — nothing is uploaded.
Can I format very large JSON files?
Yes, though extremely large files (tens of MB) may be slow since parsing happens on the main thread. For automation at scale, use the REST API or SDK instead.
What indent sizes are supported?
2-space, 4-space, and tab indentation are all supported via the format options.
Does it support JSON5 or JSONC (comments)?
No, this tool validates strict JSON per RFC 8259. For JSON with comments, use the JSON Repair tool instead.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/json-formatter \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"input":"{\"name\":\"utilix\",\"version\":1}","indent":2}'

Get an API key from your dashboard · Full API docs →

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