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How to Remove Whitespace from JSON Output in Python

When working with JSON in Python, you might need to remove or control whitespace in the output for efficiency or formatting purposes.

This guide explores how to use the json.dumps() method and its separators argument to manage whitespace, and how to handle cases where the indent argument may add whitespace.

Removing Whitespace with the separators Argument​

The json.dumps() method uses default separators, adding spaces to the output. To remove these spaces, you can set the separators argument to a tuple containing a comma and a colon:

import json

employee = {
    'name': 'Tom',
    'age': 25,
    'salary': 100,
}
json_str = json.dumps(employee, separators=(',', ':'))
print(json_str)  # Output: {"name":"Tom","age":25,"salary":100}
  • The json.dumps(employee, separators=(',', ':')) serializes the Python dictionary employee into a JSON formatted string, but overrides the default separators to comma (,) for separation of key-value pairs and colon (:) for separating keys and values.

This approach removes all spaces from the resulting JSON string.

Adding Spaces Only Between Keys and Values​

If you want spaces only between keys and values (but not between the key-value pairs) set the second element of the separators tuple to a colon followed by space (': '):

import json

employee = {
    'name': 'Tom',
    'age': 25,
    'salary': 100,
}
json_str = json.dumps(employee, separators=(',', ': '))
print(json_str)  # Output: {"name": "Tom","age": 25,"salary": 100}
  • The separators tuple is set to (',', ': ') which will put space only after the colon character.

Adding Spaces Only Between Key-Value Pairs​

Conversely, to add a space only between the key-value pairs, use a comma followed by a space (', ') as the first element of the separators tuple:

import json

employee = {
    'name': 'Tom',
    'age': 25,
    'salary': 100,
}
json_str = json.dumps(employee, separators=(', ', ':'))
print(json_str) # Output: {"name":"Tom", "age":25, "salary":100}
  • The separators tuple is set to (', ', ':') which will put a space only after the comma character.

Avoiding Whitespace from indent​

If you still have whitespace in your JSON string, then you are likely using the indent parameter, set it to None or omit it from your call to json.dumps():

import json
employee = {
    'name': 'Tom',
    'age': 25,
    'salary': 100,
}

json_str = json.dumps(employee, indent=4, separators=(',', ':'))
print(json_str)

Output:

{
    "name":"Tom",
    "age":25,
    "salary":100
}
  • Setting the indent parameter causes the JSON string to be pretty printed, with added newlines and whitespaces.
note

Make sure to omit the indent argument or explicitly set it to None to get a minified string output without any spaces.

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