HTTP registry: 0x33

Datagram or Capsule Protocol parse error

HTTP/3 registry values apply to QUIC-backed streams, frames, settings, or protocol negotiation. 0x33 is permanent in HTTP/3 Error Codes. Defining reference: rfc9297.

httpregistryhttp3-parametershttp3-parameters-error-codes

Identifier (http)

0x33

Datagram or Capsule Protocol parse error

Preserve HTTP semantics while accounting for QUIC migration, TLS/ALPN negotiation, and early-data replay risk.

This registry value is currently marked permanent by IANA. Follow the defining specification before sending, accepting, or proxying it.

IANA registry: http3-parameters/http3-parameters-error-codes

Registry reference: rfc9297

Sources

HTTP/3 Error Codes
rfc9297