SCALABLE, REAL-TIME MESSAGING SYSTEM

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for balancing loads in a publish-subscribe system. An example method includes identifying, by one or more computer processors, a first node from a plurality of nodes in a publish-subscribe system based at least in pan on (i) node-specific data representing loads on the plurality of nodes and (ii) channel-specific data representing a load associated with a channel comprising a channel portion to be temporarily offloaded from a second node. The method also includes selecting, by the one or more computer processors, the first node to temporarily host the channel portion of the channel. The method further includes receiving a request to access the channel portion, and granting the request to access the channel portion.