application/msgpack
applicationThe MIME type for MessagePack binary data. IANA-registered. Used in APIs that offer MessagePack as a binary alternative to JSON. Clients request it with Accept: application/msgpack. Servers that support it respond with Content-Type: application/msgpack alongside the binary payload.
Details
application/msgpack is IANA-registered for the MessagePack binary serialization format (msgpack.org spec).
Content negotiation: Client: Accept: application/msgpack, application/json;q=0.9 Server: Content-Type: application/msgpack
Alternative type: application/x-msgpack is a legacy variant still used by some libraries. Both are accepted by msgpack parsers.
When to use: offer application/msgpack as an alternative to application/json for clients that benefit from binary efficiency (lower latency mobile clients, IoT, high-frequency API consumers).
Common use
Binary API endpoints as alternative to application/json