Reactive Programming has fascinated (and confounded) developers since Microsoft’s Cloud Programmability Team released the first version of Reactive Extensions for .NET. RxJava enables Netflix to deliver at massive scale, is a fixture in Android development, and is frequently used in combination with RxJS for web development. Reactive toolkits like Eclipse Vert.x and Lightbend’s Akka have powered distributed, high volume applications from the edge to the cloud. Spring’s Reactor project renamed many of the RxJava constructs, but did little to help ease of use or flatten the substantial learning curve. Java 8 embraced reactive programming with the introduction of Streams, Lambdas, CompletionStage, and CompletableFuture. Unfortunately Java 8 also delivered a substantial learning curve. Mutiny to the rescue! SmallRye Mutiny is a reactive library that distills Reactive Programming into 2 simple concepts: Multi and Uni.