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HTTP 411 Length Required

HTTP 411 Length Required means the server requires a Content-Length header. The request contains an error or can’t be fulfilled. Retrying unchanged won’t help.

Class
4xx Client error
Standard
RFC 9110
Cacheable by default
No
Safe to retry
No
Go constant
http.StatusLengthRequired

What HTTP 411 means

Some servers refuse request bodies sent with chunked transfer encoding and need the size up front. It usually happens with a POST or PUT that has an empty body and no Content-Length: 0 header.

How to fix a 411 error

  • With curl, -d "" sends Content-Length: 0 for an empty POST.

Retrying

No. Fix the request first; sending it again unchanged will get the same response.

Example response

HTTP/1.1 411 Length Required
Date: Wed, 21 Oct 2026 10:30:00 GMT
Content-Type: application/json

How to return 411

Node.js (Express)
res.status(411).json({ error: 'Length Required' });
Python (FastAPI)
from fastapi import HTTPException

raise HTTPException(status_code=411, detail="Length Required")
Go (net/http)
http.Error(w, http.StatusText(http.StatusLengthRequired), http.StatusLengthRequired)
nginx
location /private/ {
    return 411;
}

Related status codes

Other 4xx status codes

400 Bad Request · 401 Unauthorized · 402 Payment Required · 403 Forbidden · 404 Not Found · 405 Method Not Allowed · 406 Not Acceptable · 407 Proxy Authentication Required · 408 Request Timeout · 409 Conflict · 410 Gone · 412 Precondition Failed · 413 Content Too Large · 414 URI Too Long · 415 Unsupported Media Type · 416 Range Not Satisfiable · 417 Expectation Failed · 418 I’m a Teapot · 421 Misdirected Request · 422 Unprocessable Content · 423 Locked · 424 Failed Dependency · 425 Too Early · 426 Upgrade Required · 428 Precondition Required · 429 Too Many Requests · 431 Request Header Fields Too Large · 444 No Response · 451 Unavailable For Legal Reasons · 499 Client Closed Request

See the full list of HTTP status codes.

Sources

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Frequently asked questions

What does HTTP 411 Length Required mean?

HTTP 411 Length Required means the server requires a Content-Length header. Some servers refuse request bodies sent with chunked transfer encoding and need the size up front. It usually happens with a POST or PUT that has an empty body and no Content-Length: 0 header.

How do I fix HTTP 411?

With curl, -d "" sends Content-Length: 0 for an empty POST.