What would you like to know? The concept is simple so the implementation is very open to do it a million ways. They are just web socket servers that interpret events as defined by the protocol. How you handle them is up to the relay. I mean you have to handle them a certain way as defined by the protocol but I mean how you handle storing events or responding to requests is all free game. Grain for instance is inple in go and uses mongodb as a database. Strfry is in C and uses LMD. Etc. What would you like to know more about?