Asynchronous, Reactive Programming for Scala and Scala.js.
Type Name Latest commit message Commit time
Failed to load latest commit information.
benchmarks execution.AsyncQueue and catnap.ConcurrentQueue (#757) Oct 31, 2018
monix-catnap ConcurrentChannel,, Iterant#consume (#778) Nov 21, 2018
monix-eval ConcurrentChannel,, Iterant#consume (#778) Nov 21, 2018
monix-execution Fix #780: improve fixed rate scheduling on JS (#790) Dec 10, 2018
monix-java/src/main/scala/monix/java8 Expand FutureLift to take care of CompletableFuture (#761) Nov 2, 2018
monix-reactive ConcurrentChannel,, Iterant#consume (#778) Nov 21, 2018
monix-tail/shared/src ConcurrentChannel,, Iterant#consume (#778) Nov 21, 2018
monix/shared/src/main/scala/monix Add monix-catnap mention Nov 6, 2018
project ConcurrentChannel,, Iterant#consume (#778) Nov 21, 2018
reactiveTests/src/test/scala/monix/reactiveTests Iterant, version 2 (#683) Jul 4, 2018
.codecov.yml 2.3 refactorings and deprecations (#357) May 2, 2017
.gitignore Observable.bracket, Iterant/Task API refactorings, fixes (#729) Oct 6, 2018
.java-version Issue #111 - improving coverage for base Jan 20, 2016
.jvmopts Fixes #270: add atomic implementations based on atomic updaters (#272) Nov 22, 2016
.scalafmt.conf add scalafmt.conf + apply formatting (#546) Jan 22, 2018
.travis.yml Make MVar fork on async `take` (#756) Oct 29, 2018
AUTHORS Fix handling start/end of Long range in RangeObservable (#750) Oct 24, 2018 ConcurrentChannel,, Iterant#consume (#778) Nov 21, 2018 Add myself to code of conduct contacts (#720) Sep 11, 2018 Add Starting Point section to (#677) May 21, 2018
LICENSE.txt Issue #58 - Update copyright notice, again :-) Aug 20, 2015 Prepare for 3.0.0-RC2 Nov 6, 2018 Change release procedure Feb 25, 2018
build.sbt Use globally accessible (rather than local) source paths in JS source… Nov 25, 2018
codecov.yml Add scanEval for Iterant / Observable and Task.fromEffect (#412) Aug 11, 2017
rootdoc.txt Add monix-catnap mention Nov 6, 2018


Asynchronous, Reactive Programming for Scala and Scala.js.

Build Status Coverage Status Maven Central



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


See monix-sample for a project exemplifying Monix used both on the server and on the client.


The packages are published on Maven Central.

  • Stable release: 2.3.3
  • Current release candidate: 3.0.0-RC2 (compatible with Cats-Effect 1.0.0)

For the 3.x series (that works with Cats 1.x and Cats-Effect 1.0.0):

libraryDependencies += "io.monix" %% "monix" % "3.0.0-RC2"

For the 2.x series:

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


Monix 3.x is modular by design, so you can pick and choose:

  • monix-execution exposes the low-level execution environment, or more precisely Scheduler, Cancelable, Atomic and CancelableFuture; depends on Cats 1.x and Cats-Effect
  • monix-eval exposes Task, Coeval; depends on monix-execution
  • monix-reactive exposes Observable for modeling reactive, push-based streams with back-pressure; depends on monix-eval
  • monix-tail exposes Iterant streams for purely functional pull based streaming; depends on monix-eval and makes heavy use of Cats-Effect
  • monix provides all of the above

Versioning Scheme

The versioning scheme follows the Semantic Versioning (semver) specification, meaning that stable versions have the form $major.$minor.$patch, such that:

  1. $major version updates make binary incompatible API changes
  2. $minor version updates adds functionality in a backwards-compatible manner, and
  3. $patch version updates makes backwards-compatible bug fixes

For development snapshots may be published to Sonatype at any time. Development versions have the form: $major.$minor.$patch-$hash (example 3.0.0-d3288bb).

The $hash is the 7 character git hash prefix of the commit from which the snapshot was published. Thus, "snapshots" can be used as repeatable upstream dependencies if you're feeling courageous. NO GUARANTEE is made for upgrades of development versions, use these at your own risk.



API Documentation:

(contributions are welcome)



The Monix project welcomes contributions from anybody wishing to participate. All code or documentation that is provided must be licensed with the same license that Monix is licensed with (Apache 2.0, see LICENSE.txt).

People are expected to follow the Scala Code of Conduct when discussing Monix on GitHub, Gitter channel, or other venues.

Feel free to open an issue if you notice a bug, have an idea for a feature, or have a question about the code. Pull requests are also gladly accepted. For more information, check out the contributor guide.

If you'd like to donate in order to help with ongoing maintenance:


All code in this repository is licensed under the Apache License, Version 2.0. See LICENCE.txt.


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.