JSON API compliant channel communication

I’m wondering how I can make my channel communication (with front-end) JSON API compliant ( http://jsonapi.org/)? I have used js_serializer in controllers, but how to go about it in socket communication? And please correct me if I’m wrong, but it looks like the default communication is in JSON. Where is this format defined and who is doing the serialization/deserialization?

Another noob question: Does it even make sense to talk about message formats in socket communication? I guess it does, but I’m not sure. I say that because it doesn’t look like there’s any place to specify content type or anything in socket communication.