# scalaz/scalaz

Principled Functional Programming in Scala

Repository: https://github.com/scalaz/scalaz
Canonical: https://ross.abutalabs.com/products/scalaz
Language: Scala
License: NOASSERTION
License Family: other
Topics: scalaz, scala, functional-programming, scala-native, scalajs
Last push: 2026-08-24T22:08:56+00:00

## Health v2 (maintenance only)
Score: 77/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 35, longevity 100
- inputs: {"age_days": 6073, "days_push": 9, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4673, forks 698 (observed 2026-08-28T04:08:56.661999+00:00)

## What it is
Scalaz is a Scala library for principled functional programming, providing purely functional data structures and foundational type classes such as Functor and Monad with instances for many data types. It is cross-built for Scala 2.12/2.13/3, Scala.js, and Scala Native.

## Use cases
- use monads and functors in Scala
- purely functional data structures for Scala
- type class instances for Option and List
- write functional programming code in Scala
- traverse and apply operations functionally
- cross-compile Scala code to JS and native

## When to choose
- you want a mature, principled FP library for Scala with type classes like Monad and Functor
- you need purely functional data structures such as NonEmptyList and Tree
- you need cross-building support for Scala.js and Scala Native

## When to avoid
- you prefer the Cats ecosystem or ZIO ecosystem for FP in Scala
- you want a lightweight minimal dependency and don't need advanced type classes
- your team is not familiar with functional programming concepts

## Facets
- artifact type: library
- maturity: stable
- function: serialization, developer-tools
- domain: programming-languages, developer-tools
- platform: jvm, cross-platform
- tags: scala, functional-programming, type-classes, monads, functors, purely-functional-data-structures, scala-js, scala-native, algorithms

## Member repositories
- scalaz/scalaz (main) score 77

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:56.661999+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 2026-08-29T18:19:22.506822+00:00, confidence not recorded.
  - readme: https://github.com/scalaz/scalaz (fetched 2026-08-28T04:08:56.661999+00:00, sha d11459d23155)
- Data as of 2026-08-30T08:39:29.467469+00:00.