HTTP 411 Length Required vs 422 Unprocessable Content
Both HTTP 411 (Length Required) and 422 (Unprocessable Content) belong to the 4xx Client Error category. 411 indicates that the server refuses to accept the request without a Content-Length header. Meanwhile, 422 means that the server understands the content type and syntax, but was unable to process the contained instructions. Common in API validation errors.
Description
The server refuses to accept the request without a Content-Length header.
When You See It
When sending a request body without specifying Content-Length.
How to Fix
Include a Content-Length header in your request.
Description
The server understands the content type and syntax, but was unable to process the contained instructions. Common in API validation errors.
When You See It
When form validation fails — correct syntax but invalid data (e.g., email format wrong, date in the past).
How to Fix
Check the response body for specific validation errors and correct the input data.
Key Differences
HTTP 411: The server refuses to accept the request without a Content-Length header.
HTTP 422: The server understands the content type and syntax, but was unable to process the contained instructions. Common in API validation errors.
You encounter 411 when when sending a request body without specifying Content-Length.
You encounter 422 when when form validation fails — correct syntax but invalid data (e.g., email format wrong, date in the past).
When to Use Which
For 411 (Length Required): Include a Content-Length header in your request. For 422 (Unprocessable Content): Check the response body for specific validation errors and correct the input data.