SFP modules, or Small Form-factor Pluggable modules, are compact, hot-swappable transceivers used in networking equipment like switches, routers, and network cards. They support various communication standards, including Ethernet, Fibre Channel, and SONET/SDH, and come in different types (e.g., SFP, SFP+, QSFP, QSFP28) to handle different speeds and distances. They enable flexible and scalable network connectivity.