ValueError: Request body must be bytes or str

ValueError: invalid body type

$ python -c "import requests; requests.post('https://example.com', data=object())"
Traceback (most recent call last):
  ...
TypeError: Object of type 'object' is not JSON serializable

Why this happens

Requests expects data as bytes or str, or json as JSON-serializable types. Providing arbitrary objects fails.

Fix

• Convert data to bytes/str or use the json= parameter with serializable types.

Wrong code

import requests
payload = object()  # not serializable
requests.post("https://example.com/api", json=payload)

Fixed code

import requests
payload = {"name": "alice", "age": 30}
response = requests.post("https://example.com/api", json=payload)
print(response.status_code)