ZeroRPC is a light-weight, reliable and language-agnostic library for distributed communication between server-side processes. It builds on top of ZeroMQ and MessagePack. Support for streamed responses – similar to python generators – makes ZeroRPC more than a typical RPC engine. Built-in heartbeats and timeouts detect and recover from failed requests. Introspective capabilities, first-class exceptions and the command-line utility make debugging easy. ZeroRPC powers the infrastructure behind dotCloud.