JSON Formatter

Beautify, minify, validate, and inspect JSON documents locally.

About this tool

Format and inspect JSON locally with clear structural statistics

JSON Formatter validates one JSON document—including object, array, string, number, boolean, and null roots—then beautifies it with exactly 2 or 4 spaces or minifies it, and reports value-type counts and maximum depth. Work stays in your browser, with a 1,000,000 UTF-16 code-unit input and output limit.

How to use it

  1. Paste a single JSON document or load the built-in sample.
  2. Choose Beautify or Minify; indentation applies to Beautify, then let the local worker inspect the current source.
  3. Review the root type, total values, object, array, string, number, boolean, null, and depth statistics before copying the current JSON output.

Useful for

  • Confirm that an API payload or configuration snippet has valid JSON syntax before using it.
  • Reformat compact JSON for code review while preserving native JavaScript JSON behavior.
  • Minify a validated JSON payload for transport without uploading it.
  • Estimate document structure and nesting from bounded local statistics without uploading data.

Frequently asked questions

Does JSON validation prove that the data matches a schema?

No. This inspector proves JSON syntax only. It does not validate a schema, repair input, sort keys, or establish that values are trustworthy.

How are duplicate keys, large numbers, and integer-like keys handled?

The tool uses native JSON parsing: the last duplicate key wins, numbers use JavaScript binary64 and may be respelled, and integer-like object keys may appear in native enumeration order.

Does JSON Formatter upload or retain my document?

No. Inspection runs in a dedicated browser worker, no network request is made, and the current payload is kept only in memory for the open tool session.