# monix/monix

Asynchronous, Reactive Programming for Scala and Scala.js.

Repository: https://github.com/monix/monix
Canonical: https://ross.abutalabs.com/products/monix
Homepage: https://monix.io
Language: Scala
License: Apache-2.0
License Family: permissive
Topics: scala, monix, typelevel, functional-programming, reactive-programming, fp, cats, reactive-streams, reactivex, cats-effect
Last push: 2026-08-25T06:14:09+00:00

## Health v2 (maintenance only)
Score: 88/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 67, longevity 100
- inputs: {"age_days": 4622, "days_push": 8, "days_rel": 10, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1928, forks 243 (observed 2026-08-28T04:05:55.801804+00:00)

## What it is
Monix is a high-performance Scala and Scala.js library for composing asynchronous, event-based programs, offering data types like Observable, Task, Coeval, and Iterant. It is a Typelevel project that implements ReactiveX with functional programming principles, back-pressure support, and Reactive Streams compatibility, and was one of the parents of Cats Effect.

## Use cases
- compose asynchronous event-based programs in Scala
- build reactive streaming pipelines with back-pressure
- replace Scala Future with a principled Task for effect management
- handle resource acquisition and release safely in async code
- stream data pull-based with Iterant
- write code that runs on both JVM and JavaScript via Scala.js
- manage concurrency with purely functional primitives like MVar and Circuit Breaker

## When to choose
- you need ReactiveX-style observables in Scala with strong FP foundations
- you want Reactive Streams compatibility and back-pressure out of the box
- you are on the Typelevel stack (Cats, Cats Effect 2.x) and need Task/Observable abstractions
- you need cross-compilation between JVM and Scala.js

## When to avoid
- you are starting a new project on Cats Effect 3.x, where fs2 and CE3 idioms are the standard
- you only need simple futures without effect abstractions
- you want a library with rapid ongoing development, as Monix is largely in maintenance mode

## Facets
- artifact type: library
- maturity: maintenance
- function: concurrency, streaming, developer-tools
- domain: backend, cross-platform
- platform: jvm, cross-platform
- tags: reactive-streams, cats-effect, typelevel, observable, task, backpressure, scala-js, functional-programming, reactive-programming, javascript

## Member repositories
- monix/monix (main) score 88

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:55.801804+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:09:07.907351+00:00, confidence not recorded.
  - readme: https://github.com/monix/monix (fetched 2026-08-28T04:05:55.801804+00:00, sha 8a12cf5f4d49)
  - homepage: https://monix.io (fetched 2026-08-29T10:48:37.667886+00:00, sha 335b4f77a14a)
  - site_page: https://monix.io/docs/current (fetched 2026-08-29T10:48:37.671019+00:00, sha 17335f9d3e45)
  - site_page: https://monix.io/docs/current/intro/usage.html (fetched 2026-08-29T10:48:37.673151+00:00, sha 3c3f6bb2cb86)
  - site_page: https://monix.io/docs/current/intro/versioning-scheme.html (fetched 2026-08-29T10:48:37.674915+00:00, sha 705b9bfa099a)
  - site_page: https://monix.io/docs/3x (fetched 2026-08-29T10:48:37.676861+00:00, sha 97cf2a04285c)
  - site_page: https://monix.io/docs/2x (fetched 2026-08-29T10:48:37.679068+00:00, sha 27874c7dc787)
- Data as of 2026-08-30T08:39:29.467469+00:00.