River is a protocol for building decentralized real-time messaging apps. It consists of an EVM-compatible L2 chain, decentralized off-chain stream nodes, and smart contracts that are deployed on Base. River allows people to create programmable communication use cases, referred to as “Spaces,” in a permissionless manner. These Spaces are ownable, feature on-chain subscriptions (”Memberships”), extendable reputation system, and end-to-end message encryption.