import json # We're opening file for writing operations using with statement, to be sure # that it would be closed as soon as we would be done with editing. with open('file.json', 'w') as f: json.dump({ "list": [1, 2, 3, 4], "comment": "List of 4 first natural numbers" }, f, indent=4) # Lets check its content. data = json.load(open('file.json')) print json.dumps(data, indent=4)