WAMPv1 uses JSON as a message payload format. This is simple, fulfills its purpose, and has some nice aspects: JSON parsers/serializers are available for many languages/platfoms for browsers, JSON is builtin and native its not perfect, but works However, there are (at least) 2 situations where JSON is a pain: I need to transfer binary data .. i.e. load WebGL textures, vectors, sound whatever via W