DIM is an open source project of decentralized instant messaging protocol, as well as the name of the open communication platform built on top of this protocol. DIM has a wide usage from building a social network product, exchanging data between blockchains or enterprises, to bridging programs in Internet of Things. This is achieved by combining many innovations, such as asymmetric cryptography, extensible and high-performance service nodes, and the address naming service. DIM is the new generation of communication standard to drive the future internet.