Wendy does one thing, and it does it very well: it lets a cluster of servers become self-organising. That means servers can send messages between each other with no central hub, no single point of failure. Servers, referred to as Nodes, can simply announce their presence and begin passing messages with the rest of the group.
Using Wendy is simple. You create a Node and build a Cluster around it. If this is the first Node to join, that’s it, you’re done! If there’s already a Node in the Cluster, you simply announce your presence to it. That Node will take care of telling the other Nodes, and they’ll all tell you about the other Nodes in the Cluster. Then you can just start passing messages. When a Node leaves, you’ll just reroute the message to a new Node, and the Cluster will move on. For code examples on how to accomplish all of this, check the README or the documentation.