XMTP is an open, composable, and decentralized communication network for blockchain wallets that allows for messaging, notifications, and group chat capabilities. It is built using Waku and Libp2p and messages are persisted in nodes of the XMTP Network. The XMTP SDK provides functionality for wallet authentication, key management, message sending and retrieval, and supports Ethereum wallets. Hackathon ideas proposed using XMTP and Livepeer to build a video chat app or send video access codes via chat. The roadmap includes further decentralizing the network and adding client implementations in more languages.