The JSON object must be str, bytes or bytearray, not dict

The JSON object must be str, bytes or bytearray, not dict #

The Python "TypeError: the JSON object must be str, bytes or bytearray, not dict" occurs when we pass a dictionary to the json.loads() method. To solve the error, remove the call to json.loads() and use the json.dumps() method if trying to convert the dict to a JSON string.

Here is an example of how the error occurs.

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import json

my_dict = {'name': 'Alice', 'age': 30}

# ⛔️ TypeError: the JSON object must be str, bytes or bytearray, not dict
result = json.loads(my_dict)

The json.loads method parses a JSON string into a native Python object.

If you need to convert a dictionary to a JSON string, use the json.dumps() method.

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import json

my_dict = {'name': 'Alice', 'age': 30}

my_json_str = json.dumps(my_dict)

print(my_json_str)  # 👉️ '{"name": "Alice", "age": 30}'
print(type(my_json_str))  # 👉️ <class 'str'>

The json.dumps method converts a Python object to a JSON formatted string.

In other words, if you need to parse a JSON string into a native Python object, you have to use the json.loads() method, and if you need to convert a Python object into a JSON string, you have to use the json.dumps() method.

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import json

json_str = r'{"name": "Alice", "age": 30}'


# ✅ parse JSON string to Python native dict
my_dict = json.loads(json_str)
print(type(my_dict))  # 👉️ <class 'dict'>

# ✅ convert Python native dict to a JSON string
my_json_str = json.dumps(my_dict)
print(type(my_json_str))  # 👉️ <class 'str'>

The json.loads() method basically helps us load a Python native object (e.g. a dictionary or a list) from a JSON string.

If you need to read from a json file, use the json.load() method.

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import json

file_name = 'example.json'

with open(file_name, 'r', encoding='utf-8') as f:
    my_data = json.load(f)

    print(my_data)  # 👉️ {'name': 'Alice', 'age': 30}
    print(my_data['name'])  # 👉️ 'Alice'
    print(type(my_data))  # 👉️ <class 'dict'>

The code sample above assumes that you have an example.json file in the same directory.

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{"name": "Alice", "age": 30}

The json.load method is used to deserialize a file to a Python object, whereas the json.loads method is used to deserialize a JSON string to a Python object.

The json.load() method expects a text file or a binary file containing a JSON document that implements a .read() method.

The JSONEncoder class supports the following objects and types by default.

If you aren't sure what type of object a variable stores, use the built-in type() class.

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my_dict = {'name': 'Alice', 'age': 30}
print(type(my_dict))  # 👉️ <class 'dict'>
print(isinstance(my_dict, dict))  # 👉️ True


my_str = 'hello world'
print(type(my_str))  # 👉️ <class 'str'>
print(isinstance(my_str, str))  # 👉️ True

The type class returns the type of an object.

The isinstance function returns True if the passed in object is an instance or a subclass of the passed in class.

Conclusion #

The Python "TypeError: the JSON object must be str, bytes or bytearray, not dict" occurs when we pass a dictionary to the json.loads() method. To solve the error, remove the call to json.loads() and use the json.dumps() method if trying to convert the dict to a JSON string.