Asynchronous Programming for Scala and Scala.js.


Monix is a high-performance Scala / Scala.js library for composing asynchronous, event-based programs.

It started as a proper implementation of ReactiveX, with stronger functional programming influences and designed from the ground up for back-pressure and made to cleanly interact with Scala’s standard library, compatible out-of-the-box with the Reactive Streams protocol. It then expanded to include abstractions for suspending side effects and for resource handling, being one of the parents and implementors of cats-effect.

A Typelevel project, Monix proudly exemplifies pure, typeful, functional programming in Scala, while making no compromise on performance.


  • exposes the kick-ass Observable, Iterant, Task and Coeval data types, along with all the support they need
  • modular, only use what you need
  • designed for true asynchronicity, running on both the JVM and Scala.js
  • really good test coverage, code quality and API documentation as a primary project policy


Featured presentation:

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Download and Usage

The packages are published on Maven Central.

In SBT for the latest 3.x release that integrates with Typelevel Cats out of the box (use the %%% for Scala.js):

libraryDependencies += "io.monix" %% "monix" % "3.0.0"

Or for the older 2.x release:

libraryDependencies += "io.monix" %% "monix" % "2.3.3"

Monix is modular by design, so you can have an à la carte experience, the project being divided in multiple sub-projects.

See Usage in SBT and Maven for more details.


Documentation and tutorials:

API ScalaDoc:

Relevant links to dependencies:

Latest News

  1. Monix 3.0.0
  2. Monix: Version 3.0.0-RC5
  3. Monix: Version 3.0.0-RC4
  4. Monix: Version 3.0.0-RC3
  5. Converting Scala's Future to Task (Video)


YourKit supports the Monix project with its full-featured Java Profiler. YourKit, LLC is the creator YourKit Java Profiler and YourKit .NET Profiler, innovative and intelligent tools for profiling Java and .NET applications.

Development of Monix has been initiated by Eloquentix engineers, with Monix being introduced at E.ON Connecting Energies, powering the next generation energy grid solutions.


Copyright (c) 2014-2019 by The Monix Project Developers.
See the project homepage at:

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.