Not sure about this one. JSON has a lot of advantages, size is negligible compared to media files people transfer all the time. What relays should provide, next to websockets is a plain HTTP API. This lowers the bar even more for new nostr developers and makes things easier for prototype and lots of no-realtime apps (not having to handle closing sockets, reconnection logic, etc). You can have both served in the same path on the same process. Imo this should've been part of the spec, it might be too late nostr:note142wvcpyyla0zv4lpnfnaj00yvx5xyh3edj0cxsuwgme83ldeky3sfvva7r