Messages

Underpinning the Nostr Protocol is a relatively simplistic messaging system by which clients (read: applications) communicate with relays (read: databases) to retrieve and store data in a JSON format. This communication process is documented in more detail in NIP-01 - Communication between clients and relays but at a very high level is broken down into three main components:

Client Messages - Which define the specific formats/structure by which communication from the client to the relay is performed
Relay Messages - The pre-defined ways in which relays will communicate with/respond to clients

The messages themselves (for both client and relay) are passed in the form of a JSON array where the first item in the array is used to identify the type of message (e.g. "EVENT") and the subsequent items provide the relevant parameter values associated with the message in the order specified by the protocol documentation.

Navigate to the relevant sections linked above to see the implementation of the communication rules in more detail.