HTTP Status Code 411 = “Length Required”

The server refuses to process the request because the Content-Length header is missing.

Why this happens

Some servers require the client to specify the exact size of the request body before accepting the request.

If the request does not include:

http id=”m7q2we”
Content-Length

the server may return:

http id=”v4k8ra”
HTTP/1.1 411 Length Required

Example

Problematic request

http id=”n3p1xd”
POST /upload HTTP/1.1
Content-Type: application/json

Missing:

http id=”u8w5kc”
Content-Length: 123

Correct request

http id=”g7q2mv”
POST /upload HTTP/1.1
Content-Type: application/json
Content-Length: 27

Common causes

• Improper HTTP client configuration
• Custom socket requests
• Proxy/load balancer restrictions
• Missing headers in APIs
• Streaming/chunked request issues

Fixes

1. Add Content-Length header

JavaScript fetch

Usually automatic:

js id=”r5k9zn”
fetch(‘/api’, {
method: ‘POST’,
body: JSON.stringify(data)
});

2. Node.js example

js id=”t2p4xe”
const body = JSON.stringify(data);

fetch(url, {
method: ‘POST’,
headers: {
‘Content-Length’: body.length
},
body
});

3. PHP cURL

cURL usually sets it automatically:

php id=”q6m3yt”
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

4. Python requests

Automatically handled:

python id=”w9k1vc”
requests.post(url, json=data)

Special case: chunked transfer

If using:

http id=”p4q7ra”
Transfer-Encoding: chunked

some servers may not require Content-Length.

Difference between 411 and 413

| Code | Meaning |
| — | – |
| 411 | Missing Content-Length |
| 413 | Payload too large |

Related HTTP status codes

| Code | Meaning |
| — | – |
| 400 | Bad Request |
| 411 | Length Required |
| 412 | Precondition Failed |
| 413 | Payload Too Large |
| 415 | Unsupported Media Type |