Typelevel JVM

argonaut-shapeless

Automatic derivation for argonaut

banana-rdf

RDF, SPARQL and Linked Data technologies

cats-actors

An Actor Model implementation built on top of Cats-Effect, providing a higher-level abstraction for managing concurrency.

case-insensitive

A case-insensitive string for Scala

catapult

A thin wrapper for the Launch Darkly Java server SDK using cats-effect and fs2

catbird

Cats instances for various Twitter Open Source Scala projects

Cats

A library intended to provide abstractions for functional programming in Scala, leveraging its unique features. Design goals are approachability, modularity, documentation and efficiency.

Cats Collections

Data structures that facilitate pure functional programming with cats

Cats-Effect

The IO Monad for Scala, plus type classes for general effect types.

Cats MTL

Monad transformers made easy

cats-parse

A parsing library for the cats ecosystem

cats-scalatest

Scalatest bindings for Cats.

cats-stm

A STM implementation for Cats Effect

Cats Tagless

A library of utilities for tagless final algebras

Cats-Time

Instances for Cats Typeclasses for Java 8 Time

Circe

Yet another JSON library for Scala

Ciris

Functional Configurations for Scala

coulomb

A statically typed unit analysis library for Scala

cron4s

Cross-platform CRON expression parsing for Scala

decline

A composable command-line parser for Scala.

discipline

Originally intended for internal use in spire, this library helps libraries declaring type classes to precisely state the laws which instances need to satisfy, and takes care of not checking derived laws multiple times.

doobie

A pure functional JDBC layer for Scala. It is not an ORM, nor is it a relational algebra; it just provides a principled way to construct programs (and higher-level libraries) that use JDBC.

edomata

Event-driven automata for Scala, Scala.js and scala native. This library provides purely functional state machines that can be used to create event sourced and/or CQRS style applications. It also includes production ready backends.

eff

Extensible effects are an alternative to monad transformers for computing with effects in a functional way. This library is based on the “free-er” monad and an “open union” of effects described by Oleg Kiselyov in “Freer monads, more extensible effects”

endless4s

Sharded and event-sourced entities using tagless-final algebras

Extruder

Populate case classes from any configuration source

fabric

Object-Notation Abstraction for JSON, binary, HOCON, etc.

Feral

Feral cats are homeless, feral functions are serverless

Fetch

Library built on top of Cats that provides efficient data access from heterogeneous dataurces

Finch

Purely functional basic blocks atop of Finagle for building composable HTTP APIs

Frameless

Frameless is a library for working with Spark using more expressive types.

fs2-aes

Micro library providing AES encryption/decryption of fs2.Stream[F, Byte].

fs2-compress

Compression Algorithms for Fs2

fs2-data

Parse and transform data (CBOR, CSV, JSON, XML) in a streaming manner

fs2-grpc

gRPC implementation for FS2/cats-effect

fs2

FS2 is a library for purely functional, effectful, and polymorphic stream processing library in the Scala programming language. Its design goals are compositionality, expressiveness, resource safety, and speed. The name is a modified acronym for Functional Streams for Scala (FSS, or FS2).

Grackle

Functional GraphQL server for the Typelevel stack

Hammock

Purely functional HTTP client

http4s

A typeful, purely functional HTTP library for client and server applications

imp

Summoning implicit values

jawn-fs2

Integration of jawn and fs2 for streaming, incremental JSON parsing

keypool

A Keyed Pool Implementation for Scala

kind-projector

Plugin for nicer type-lambda syntax

Kittens

Automatic type class derivation

Laika

Site and e-book generator and customizable text markup transformer for sbt, Scala and Scala.js

LDBC

Pure functional JDBC layer with Cats Effect 3 and Scala 3

Lepus

Purely functional, non-blocking RabbitMQ client for scala, scala js and scala native built on top of fs2.

Libra

Compile time dimensional analysis for any problem domain

literally

Compile time validation of literal values built from strings

log4cats

Logging Tools For Interaction with cats-effect

Monix

High-performance library for composing asynchronous, event-based programs, exposing a Reactive Streams implementation along with primitives for dealing with concurrency and side-effects.

Monocle

Optics library offering a simple yet powerful API to access and transform immutable data

Mouse

Enrichments to standard library classes to ease functional programming

Natchez

functional tracing for cats

otel4s

An OpenTelemetry library based on cats-effect

parsley-cats

The parsley-cats library exposes Cats instances for Parsley parsing library.

Peloton

An actor library for Cats Effect

perspective

Provides tools for generic programming, and typeclasses for monad transformers and higher kinded data.

PureConfig

A boilerplate-free library for loading configuration files

refined

Tools for refining types with type-level predicates which constrain the set of values described by the refined type, for example restricting to positive or negative numbers.

ScalaCheck

ScalaCheck is a library for automated property-based testing. It contains generators for randomized test data and combinators for properties.

scalacheck-shapeless

Automatic derivation for ScalaCheck

Scala Exercises

Platform and framework for Scala devs to learn about Scala libraries

scala-steward

A robot that helps keeping Scala projects up-to-date

scodec

scodec is a combinator library for working with binary data. It focuses on contract-first and pure functional encoding and decoding of binary data and provides integration with shapeless.

Scoverage

Code coverage tool for Scala

Shapeless

Shapeless is a generic programming library. Starting with implementations of Scrap your boilerplate and higher rank polymorphism in Scala, it quickly grew to provide advanced abstract tools like heterogenous lists and automatic instance derivation for type classes.

simulacrum

First-class syntax for type classes

Simulacrum Scalafix

Simulacrum as Scalafix rules

singleton-ops

Operations for primitive and String singleton types

Skunk

A data access library for Scala + Postgres

sonic

Property-based testing with integrated shrinking

specs2

specs2 is a library for writing executable software specifications, aiming for conciseness, readability and extensibility.

spire

Spire is a numeric library for Scala which is intended to be generic, fast, and precise. Using features such as specialization, macros, type classes, and implicits, Spire works hard to defy conventional wisdom around performance and precision trade-offs.

Squants

The Scala API for Quantities, Units of Measure and Dimensional Analysis

Twiddles

Micro-library for building effectful protocols

TwoTails

A compiler plugin adding support for mutual tail recursion

typelevel.g8

A Giter8 template for sbt-typelevel

typelevel-nix

Development tools for Typelevel projects

uniform-scala

Functional user journeys

upperbound

A purely functional, interval based rate limiter

vault

Type-safe, persistent storage for values of arbitrary types