You have to compile the protocol buffers so there is overhead. Also the messages aren't human readable eg through kafka so you need to write something to look t

You have to compile the protocol buffers so there is overhead. Also the messages aren't human readable eg through kafka so you need to write something to look through the messages. JSON is faster if your dev team need to get from A to B in a hurry, but protocol buffers are a generally a better long term choice if you can put in the effort up front. Both have pros and cons.