Matrix homeservers use the Federation APIs (also known as server-server APIs) to communicate with each other. Homeservers use these APIs to push messages to each other in real-time, to retrieve historic messages from each other, and to query profile and presence information about users on each other’s servers. The APIs are implemented using HTTPS requests between each of the servers. These HTTPS requests are strongly authenticated using public key signatures at the TLS transport layer and u...
