100% local JSON tool

JSON Minify & Unminify Online

Paste JSON, make it smaller or readable, then copy the result. Nothing is uploaded.

Local processing · private

Input JSON6 lines · 143 B

Ctrl/⌘ + Enter to runPaste, type, or drop a .json file

Result

{"site":"jsonminify.org","private":true,"tools":["minify","format","validate"],"settings":{"indent":2,"download":true}}

119 B · 24 B saved✓ Valid JSON

Original size143 B

Result size119 B

Reduction16.8%

StatusValid JSON

No account · no upload · no installation

Processed in your browser

Standard JSON validation

No account or upload

01 — 03

Smaller, valid JSON in three steps

The tool validates before it transforms, so invalid input never becomes a misleading result.

Add your JSON

Paste text, load the example, or open a local .json file up to 10 MB.

Minify or unminify

Remove optional whitespace or format the data with two or four spaces.

Copy or download

Review the UTF-8 byte change, then use the valid result wherever you need it.

EXAMPLES & SYNTAX

Input, output, and common errors

The parser preserves JSON values while changing only the representation required by this tool.

INPUT

{
  "site": "jsonminify.org",
  "enabled": true,
  "items": [1, 2]
}

OUTPUT

{"site":"jsonminify.org","enabled":true,"items":[1,2]}

CaseValid formWhy it matters

Object keys{"name":"value"}

Keys and string values require double quotes.

Arrays[1, 2, 3]

Items keep their original order.

Primitive valuestrue · false · null

These tokens are lowercase and are not quoted.

Whitespacespace · tab · line break

Optional outside strings; meaningful inside quoted strings.

Invalid JSON example{ "enabled": true, }

A trailing comma is valid in some JavaScript contexts but not in JSON. Remove it before running parsed operations.

WHY JSONMINIFY.ORG

A focused JSON tool that respects your data

Standard browser APIs do the work. There is no account, upload queue, or hidden repair step.

Browser-local processing

Your JSON is parsed on this device and is not sent to our server.

Standards-based validation

Strict JSON.parse behavior catches comments, trailing commas, and unquoted keys.

Useful size numbers

Compare actual UTF-8 bytes before and after minifying instead of character counts.

COMMON USE CASES

Where JSON minification is useful

Minification is most useful when whitespace adds no value to the next system or person receiving the data.

API request and response samples

Reduce large copied payloads before saving them as fixtures, attaching them to bug reports, or moving them between development tools.

Embedded application data

Compact JSON placed in HTML data blocks, static assets, or generated application bundles where optional formatting increases transfer size.

Configuration handoff

Produce a clean single-line value for environment variables, command-line arguments, and systems that expect compact JSON text.

Test data and logs

Normalize valid JSON into a predictable compact form before comparing fixtures, storing examples, or sharing diagnostic output.

JSON REFERENCE

What JSON minification changes—and what it does not

A minifier should remove presentation whitespace while preserving the parsed JSON value. Understanding that boundary prevents accidental data changes.

Optional whitespace is removed

Spaces, tabs, and line breaks between JSON tokens are not part of the data model. After parsing succeeds, the tool serializes the value without optional whitespace.

Invalid syntax is never disguised

Comments, trailing commas, unquoted property names, undefined, and JavaScript expressions are not standard JSON. The tool reports an error instead of silently guessing a repair.

UTF-8 bytes are measured

File size is calculated with TextEncoder, so emoji and non-Latin characters are counted by their actual UTF-8 byte length rather than by JavaScript character count.

Minified does not mean encrypted

Removing whitespace makes JSON smaller, not secret. Anyone who receives the result can parse it, so sensitive values still require appropriate access controls.

FAQ

JSON minifying, clearly explained

Straight answers about validity, privacy, file size, and what the tool changes.

Is my JSON uploaded?

No. Minifying, formatting, validation, copying, and download preparation happen in your browser. The site does not receive your JSON.

Does minifying change the data?

It removes optional whitespace after parsing standard JSON. Values remain equivalent, although object key order should not be treated as a semantic guarantee.

Why is my JSON invalid?

Standard JSON requires double-quoted keys and strings. It does not allow comments, trailing commas, undefined values, or JavaScript object literal syntax.

How large can my file be?

The local file importer accepts .json files up to 10 MB. Available device memory and browser limits can still affect unusually complex files.

What does Unminify do?

Unminify parses the JSON and writes it again with either two or four spaces of indentation, making nested data easier to read.