POST-UNSUPPORTED-CT


Test ID	`COMP-POST-UNSUPPORTED-CT`
Category	Compliance
Scored	No
RFC	RFC 9110 §15.5.16
RFC Level	MAY
Expected	`415` or `2xx`

What it sends

A POST request with an unrecognized Content-Type.

POST / HTTP/1.1\r\n
Host: localhost:8080\r\n
Content-Length: 5\r\n
Content-Type: application/x-nonsense\r\n
\r\n
hello

What the RFC says

“The 415 (Unsupported Media Type) status code indicates that the origin server is refusing to service the request because the content is in a format not supported by this method on the target resource.” — RFC 9110 §15.5.16

The server is not required to reject unsupported content types — it may choose to accept the body regardless of the declared type.

Why it matters

A server that validates Content-Type and returns 415 for unsupported formats provides better API hygiene, helping clients detect misconfigured requests early. A server that ignores unknown content types and processes the body anyway is also valid behavior — many servers treat the body as opaque bytes regardless of the declared type.

Verdicts

Pass — Server returns 415 (validates content type) or 2xx (accepts any type)
Warn — Server returns an unexpected status

Sources

RFC 9110 §15.5.16

RANGE-INVALID