Unminify JSON Online — Free JSON Prettifier

Unminify and prettify JSON instantly with our free tool. Restore readable formatting from minified JSON with detailed structural stats — all locally in your browser.

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JSON Unminification

Unminify and prettify compressed JSON online. Restore readable formatting with stats.

Features

Restore the readability of your minified JSON code by adding spaces and line breaks.

Unminify

Restore the readability of your minified JSON code by adding spaces and line breaks.

Basic example

Input JSON

{
  "name": "FastMinify",
  "version": "1.0.0",
  "description": "A fast minifier tool",
  "features": [
    "JavaScript minification",
    "CSS optimization",
    "JSON compression"
  ]
}

Minified JSON

{"name":"FastMinify","version":"1.0.0","description":"A fast minifier tool","features":["JavaScript minification","CSS optimization","JSON compression"]}

Minification options

Compression Level

Controls the aggressiveness of JSON compression

ConservativeConservative - Whitespace removal only

NormalNormal - Basic optimizations

AggressiveAggressive - Advanced optimizations and cleanup

Compression examples:

Original code

{
  "name": "test",
  "value": 42,
  "active": true,
  "items": [1, 2, 3]
}

Conservative

{"name":"test","value":42,"active":true,"items":[1,2,3]}

Normal

{"name":"test","value":42,"active":true,"items":[1,2,3]}

Aggressive

{"name":"test","value":42,"active":!0,"items":[1,2,3]}

Optimize Numbers

Optimizes number representation (removes unnecessary zeros)

Comparison with/without option:

Original code

{
  "price": 10.00,
  "count": 0,
  "rate": 1.0
}

With optimizeNumbers: true

{"price":10,"count":0,"rate":1}

With optimizeNumbers: false

{"price":10.00,"count":0,"rate":1.0}

Difference

Numbers are optimized (unnecessary zeros removed)

Remove Null Values

Removes properties with null values

Comparison with/without option:

Original code

{
  "name": "test",
  "value": null,
  "active": true,
  "count": null
}

With removeNullValues: true

{"name":"test","active":true}

With removeNullValues: false

{"name":"test","value":null,"active":true,"count":null}

Difference

Properties with null values are removed

Remove Empty Arrays

Removes empty arrays from JSON

Comparison with/without option:

Original code

{
  "name": "test",
  "items": [],
  "active": true,
  "tags": []
}

With removeEmptyArrays: true

{"name":"test","active":true}

With removeEmptyArrays: false

{"name":"test","items":[],"active":true,"tags":[]}

Difference

Empty arrays are removed

Sort Object Keys

Sorts object keys alphabetically

Comparison with/without option:

Original code

{
  "zebra": "striped",
  "apple": "red",
  "banana": "yellow"
}

With sortObjectKeys: true

{"apple":"red","banana":"yellow","zebra":"striped"}

With sortObjectKeys: false

{"zebra":"striped","apple":"red","banana":"yellow"}

Difference

Object keys are sorted alphabetically

Beautify Options

Options for formatting and beautifying JSON (Beautify only, not for Minify/Unminify)

Indentation Size

Sets the number of spaces or tabs for indentation during Beautify

Original code

{"name":"test","value":42}

With 2 spaces

{
  "name": "test",
  "value": 42
}

With 4 spaces

{
    "name": "test",
    "value": 42
}

Difference

Indentation is customizable only for Beautify. Unminify always uses 2 spaces.

Indentation Type

Use spaces or tabs for indentation during Beautify

Original code

{"name":"test","value":42}

With spaces

{
  "name": "test",
  "value": 42
}

With tabs

{
	"name": "test",
	"value": 42
}

Difference

Spaces are more standard, tabs may be preferred according to your code conventions.

JSON Statistics

Detailed information about your JSON structure

JSON statistics are automatically calculated and displayed in the results panel after each operation (Minify, Unminify, Beautify).

Keys

Objects

Arrays

Max Depth

Strings

Numbers

Booleans

Nulls

These statistics help you understand the structure and complexity of your JSON.

Dedicated JSON tools

Beyond minify/unminify on this page, FastMinify ships a full JSON cluster: JSON validator, JSON formatter, JSON diff, JSON escape / unescape, and JSON tree viewer — all browser-local.

Need JSON in YAML, CSV or XML?

Dedicated converters now live on their own topical pages — start with JSON → YAML, JSON → CSV or JSON → XML when you intentionally change serialization formats.

JSON Validation

Before minifying or formatting, validate syntax with clear line/column errors. For a dedicated workflow, use our standalone JSON validator, then explore structure in the JSON tree viewer or compare payloads with JSON diff.

JSON Formatter vs Minifier — Understanding the Difference

A JSON formatter (or beautifier) adds indentation and line breaks to make JSON readable and easy to navigate — try the dedicated JSON formatter for prettify-only workflows. A JSON minifier removes unnecessary whitespace to reduce file size for API responses. String values stay verbatim; escape embedded text via JSON escape or inspect encoding with our URL encoder and Base64 utility.