ReactiveX

RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.

A reactive programming library for JavaScript

A reactive programming library for JavaScript

Reactive Programming in Swift

RxJava bindings for Kotlin

Reactive Extensions for the Go language.

ReactiveX for Python

Reactive Extensions for C++

RxJava bindings for JavaFX

Adapter between RxJava and ReactiveStreams