When using the Python Requests library to make HTTP requests, you may occasionally see an error like:
requests.exceptions.InvalidHeader: Value for header Content-Type is invalid
This happens when Requests is unable to determine the correct Content-Type header to send with the request body.
Why Content-Type Matters
The Content-Type header tells the server what format the data is being sent in - like JSON, form data, etc. This allows the server to correctly parse and process the request body. Without the proper Content-Type, the server may reject the request or parse the data incorrectly.
There are a few common reasons you may see invalid Content-Type errors:
Here are some tips to avoid invalid Content-Type errors:
Taking a bit of extra care to ensure the request body and headers match the expected Content-Type can save you some frustrating errors! The Requests documentation contains more great examples too.