It looks like an MQTT client (including MQTT over WebSocket) is at:
https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/protocols/mqtt.html
and there also seem to be some embedded MQTT brokers available. I’d like to be able to do without a RaspberryPi (or my LattePanda).
‘A Firestorm of Pixelblaze’ over here A Firestorm of Pixelblaze - spread patterns and control via MIDI/OSC might be a more relevant place to continue. I like the idea of PBs being able to discover each other and then communicate without a broker, preferably over UDP.