IBC relayer is a software component that facilitates communication between two distinct blockchain networks that support the Inter-Blockchain Communication (IBC) protocol. The IBC protocol is a standard for the secure and reliable transfer of digital assets and data across different blockchain networks. An IBC relayer is responsible for relaying IBC packets, which are used to send messages and data between two different blockchain networks. It receives packets from one chain, verifies their authenticity and validity, and then relays them to the receiving chain.