rickynils/scalacheck

Property-based testing for Scala

scala/scala

The Scala programming language

milessabin/shapeless

Generic programming for Scala

lightbend/config

A type-safe configuration library for JVM languages

typelevel/discipline

Flexible law checking for Scala

johanandren/akka

Akka Project

paulbutcher/scalamock

Native Scala mocking framework

spray/spray

A suite of scala libraries for building and consuming RESTful web services on top of Akka: lightweight, asynchronous, non-blocking, actor-based, testable

non/spire

Powerful new number types and numeric abstractions for Scala.

julien-truffaut/monocle

Optics library for Scala

scala/scala-parser-combinators

simple combinator-based parsing for Scala. formerly part of the Scala standard library, now a separate community-maintained module

jsuereth/scala-arm

This project aims to be the Scala Incubator project for Automatic-Resource-Management in the scala library

fthomas/refined

Simple refinement types for Scala

scala-js/scala-js-dom

Statically typed DOM API for Scala.js

argonaut-io/argonaut

Purely functional JSON parser and library in scala.

monix/monix

Asynchronous, Reactive Programming for Scala and Scala.js.

slamdata/slamdata-predef

twitter/chill

Scala extensions for the Kryo serialization library

scala-native/scala-native

Your favorite language gets closer to bare metal.

milessabin/macro-compat

macro-compat is a small library which allows you to compile macros with Scala 2.10.x which are written to the Scala 2.11/2 macro API.