HTTP 411 — Length Required

The request did not specify the length of its content, which is required by the requested resource

When to use it

Use status 411 when this is the correct HTTP response semantic: The request did not specify the length of its content, which is required by the requested resource

Request and response example

GET /protected-resource HTTP/1.1
Host: api.example.com

HTTP/1.1 411 Length Required
Content-Type: application/json

{"error":"Request cannot be completed"}

Related status codes

400, 401, 402, 403

References

MDN · RFC 9110