We propose a novel, declarative approach to im-plementing reliable multi-party protocols that enables efficient and scalable implementations. Our Proper-ties Framework (PF) is able to express semantics as simple as gossip or resource cleanup, or as complex as transactions, consensus, and virtual synchrony. Protocols written in the PF compile to a hierarchical, scalable runtime infrastructure. Evaluation confirms that solutions developed this way can achieve high performance, while also benefiting from better inte-gration with the underlying runtime platform and its type system.