• ReactiveX is an API for asynchronous programming based on the observer pattern.
  • RxGo is the official Go implementation of ReactiveX (a cousin of RxJS, RxJava, etc.).
  • There are +50 new operators and multiple new features (hot vs cold observable, connectable observable, backpressure, etc.)
  • Yes, Go has already great concurrency primitives and yes, there is still no generics. Nonetheless, RxGo may still be worth a look.


In ReactiveX, the two main concepts are the Observer and the Observable.
An Observable is a bounded or unbounded stream of data. An Observer subscribes to an Observable. Then, it reacts to whatever item the Observable emits. There are operators to create or compose Observables.

  • We define a transformation function (circle into a square) using Map operator.
  • We filter each yellow square using Filter operator.

Real-World Example with v2

First, we have to install RxGo v2:

go get -u
  • Enrich each customer with a tax number. Retrieving a tax number is performed in our example by a function calling a REST service.

What Else?

As part of the new features of RxGo v2, it is now possible to:


On the v2 development:

  • 90 issues.
  • 17 participants.
  • 468 commits.
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