TypeError: Object of Type Bytes Is Not JSON Serializable

Why This Happens

JSON has no binary type. Bytes must be converted to strings: decode UTF-8 for text, or base64-encode for binary data.

The Problem

import json
data = {'content': b'Hello World'}
json.dumps(data)

The Fix

import json, base64
# For text:
data = {'content': b'Hello World'.decode('utf-8')}
# For binary:
binary = b'\x89PNG\r\n'
data = {'image': base64.b64encode(binary).decode('ascii')}
json.dumps(data)

# Or let one encoder handle bytes everywhere:
class BytesEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, bytes):
            return base64.b64encode(o).decode('ascii')
        return super().default(o)

json.dumps({'image': binary}, cls=BytesEncoder)

Step-by-Step Fix

1. 1

   Decode text bytes

   Use .decode('utf-8').

2. 2

   Base64 encode binary

   Use base64.b64encode(data).decode('ascii').

3. 3

   Use a custom encoder

   Write a JSONEncoder that handles bytes.