JSON Minify vs Pretty Print

JSON can be formatted in two ways: minified (compressed) or pretty-printed (formatted).

Pretty Print (Formatted)

const data = { name: 'John', age: 30, city: 'NYC' };

// Pretty print with 2-space indentation
const pretty = JSON.stringify(data, null, 2);

// Output:
// {
//   "name": "John",
//   "age": 30,
//   "city": "NYC"
// }

Minify (Compressed)

const data = { name: 'John', age: 30, city: 'NYC' };

// Minify - remove all whitespace
const minified = JSON.stringify(data);

// Output:
// {"name":"John","age":30,"city":"NYC"}

When to Use Each

Use Pretty Print When:

• Reading/debugging in console
• Writing to log files
• Displaying to users
• Code reviews
• Configuration files

Use Minify When:

• Sending over network (smaller size)
• Storing in databases
• API responses for bandwidth
• Caching

Size Comparison

const data = {
  users: [
    { id: 1, name: 'Alice', email: 'alice@example.com' },
    { id: 2, name: 'Bob', email: 'bob@example.com' },
    { id: 3, name: 'Charlie', email: 'charlie@example.com' }
  ]
};

const pretty = JSON.stringify(data, null, 2);
const minified = JSON.stringify(data);

console.log(`Pretty: ${pretty.length} bytes`);
console.log(`Minified: ${minified.length} bytes`);
console.log(`Savings: ${((pretty.length - minified.length) / pretty.length * 100).toFixed(1)}%`);

Real-world Example

API Response - Pretty (Development)

{
  "status": "success",
  "data": {
    "id": 123,
    "name": "Product Name",
    "price": 29.99
  }
}

API Response - Minified (Production)

{"status":"success","data":{"id":123,"name":"Product Name","price":29.99}}

Implementation

function formatJSON(json, pretty = true) {
  if (typeof json === 'string') {
    json = JSON.parse(json);
  }
  return pretty ? JSON.stringify(json, null, 2) : JSON.stringify(json);
}

Tools

# Pretty print
echo '{"a":1}' | python -m json.tool

# Minify
echo '{ "a": 1 }' | python -c "import sys,json; print(json.dumps(json.load(sys.stdin)))"

Conclusion

Use pretty print for readability during development. Use minified for production to save bandwidth. Consider content negotiation to serve appropriate format.