What does HTTP 411 mean?
The server requires a Content-Length header.
Common causes and when you see it
Sending a request body without declaring its length.
How to fix or handle it
Add the Content-Length header or use a client that sets it.
Test it yourself
Send a request with the online API tester, inspect the response with the HTTP header checker, or host an endpoint that returns 411 with the mock API generator to see how your app reacts.
HTTP 411 questions
The server requires a Content-Length header.
Sending a request body without declaring its length.
Add the Content-Length header or use a client that sets it.