A relayer is a node or a network of nodes in a blockchain system that facilitates the transfer of information or assets between different parties on the network. In the context of decentralized exchanges (DEXs), relayers match buy and sell orders and broadcast them to the network, earning fees for their services. In the context of cross-chain communication, relayers help transfer assets or messages between different blockchains and work in conjunction with oracles and validators to ensure security and accuracy. Relayers can be incentivized through economic mechanisms like transaction fees or staking requirements and are a critical component of many blockchain-based systems.