We see continued adoption and success of reactive architectures , with reactive language extensions and reactive frameworks being very popular (we added several such blips in this edition of the Radar). User interfaces, in particular, benefit greatly from a reactive style of programming. Our caveats last time still hold true: Architectures based on asynchronous message passing introduce complexity and make the overall system harder to understand—it's no longer possible to simply read the program code and understand what the system does. We recommend assessing the performance and scalability needs of your system before committing to this architectural style.
The techniques of functional reactive programming have steadily gained in popularity over recent years, and we’re seeing increased interest in extending this concept to distributed systems architectures. Partly inspired by “The Reactive Manifesto”, these reactive architectures are based on a one-way, asynchronous flow of immutable events through a network of independent processes (perhaps implemented as microservices). In the right setting, these systems are scalable and resilient and decrease the coupling between individual processing units. However, architectures based entirely on asynchronous message passing introduce complexity and often rely on proprietary frameworks. We recommend assessing the performance and scalability needs of your system before committing to this as a default architectural style.