HTTP 411 Length Required Error - Meaning & Fix

The HTTP 411 error occurs because the server requires the Content-Length header, which specifies the size of the data in the request. This header is missing, causing the server to reject the request. The error ensures data integrity by confirming the data size beforehand.

Main causes

Client sends a POST or PUT request without a Content-Length header.
Misconfigured server rejecting requests without explicit Content-Length headers.
Client uses chunked transfer encoding without properly using the Transfer-Encoding header.
Programming errors in client application where Content-Length is not calculated or set.

# Request example 
curl -X POST https://sandbox.oxylabs.io/ -H 'Accept: text/html' -H 'Accept-Encoding: br' -H 'User-Agent: Mozilla/5.0'

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Common fixes

Ensure that the Content-Length header is included in the HTTP request.
Verify that the Content-Length header value correctly matches the size of the request body.
Use tools or libraries that automatically handle the Content-Length header when building HTTP requests.
Check server configurations to confirm that it is not erroneously requiring a Content-Length header for GET or HEAD requests.

# Response example 
HTTP/1.1 411 Length Required
Content-Type: text/html; charset=UTF-8
Content-Length: 49

411 Length Required

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Common scraping HTTP error codes

401 Unauthorized	403 Forbidden	404 Not found	405 Method not allowed	406 Not acceptable
407 Proxy authentication required	408 Request timeout	409 Conflict	410 Gone	411 Length required
412 Precondition failed	413 Payload too large	414 Uri too long	415 Unsupported media type	416 Range not satisfiable
417 Expectation failed	421 Misdirected request	422 Unprocessable entity	423 Locked	424 Failed dependency
426 Upgrade required	428 Precondition required	429 Too many requests	431 Request header fields too large	444 Connection: close
451 Unavailable for legal reasons	499 Client closed request	501 Not implemented	503 Service unavailable	505 Http version not supported
506 Variant also negotiates	507 Insufficient storage	508 Loop detected	510 Not extended	511 Network authentication required