JSON minify

Pretty-printed JSON is great for reading but wastes bytes on indentation, spaces and line breaks. Minifying removes all of that without changing the data, producing the smallest valid JSON text. Smaller JSON means faster API responses, smaller files and fewer bytes in local storage, cookies or URL parameters.

How to use it

1. Paste formatted JSON.
2. Minify it. Invalid JSON is reported instead of being silently changed.
3. Copy the compact result.

Example

Input (98 bytes):

{
  'id': 42,
  'name': 'Widget',
  'tags': [
    'blue',
    'small'
  ]
}

Output (51 bytes):

{'id':42,'name':'Widget','tags':['blue','small']}

(Real JSON uses double quotes.) About half the size, with identical data.

What minification does and does not change

• Whitespace outside strings is removed.
• Whitespace inside string values is kept exactly.
• Key order, values and types are unchanged.

Is it worth it?

For API responses, gzip or Brotli compression already removes most of the cost of whitespace, so minifying adds a smaller extra gain, but it is free to do and most frameworks already send minified JSON by default. Minification matters more where compression is not applied: localStorage, cookies, message queues, database columns and query strings.

In code

• JavaScript: JSON.stringify(obj) produces minified JSON by default.
• Python: json.dumps(obj, separators=(',', ':')).
• Command line: jq -c . file.json.