Waku

Waku is a family of general-purpose messaging protocols for decentralised applications, intended to replace instant messaging and notification channels that depend on centralised servers. It is built on libp2p, routes messages with GossipSub and suppresses spam using rate-limiting nullifiers: a node publishes at the rate declared in its zero-knowledge proof, and traffic beyond that limit is rejected by the network, keeping the service usable in a permissionless setting.

The protocols are layered by function: a relay layer broadcasts across the network, light client protocols let browsers and phones send and receive without downloading full history, and a discovery protocol connects a node only to peers serving the topics it cares about, cutting bandwidth and storage overhead. Messages are sharded by topic and a store layer supports catch-up delivery. Waku serves as the communications module of the Logos stack, and projects such as Status and Railgun build private messaging and transaction broadcasting on top of it.