have a nice day, I have a problem. IOT devices exist, but they provide communication with different iot protocols (mqtt, xmpp, etc.). Can I listen to a single code snippet on the server they send? Which libraries should I research? I'm sorry for my English. thanks.
There is no single library that can serve XMPP, MQTT and CoAP because they all have fundamentally different data models. XMPP is about sending messages between arbitrary devices, MQTT is about providing values for topics, CoAP is about representations of resource state.
High-level gateway software exists that speaks multiple protocols (eg. home assistant), but that's not a library any more.