Projects

Our projects cover a wide range of domains, from general functional programming to tooling.

algebra

A solid foundation of basic algebra type classes such as groups and rings aiming to serve as a consistent foundation for multiple libraries.

Basic type classes

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argonaut-shapeless

Automatic derivation for argonaut

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banana-rdf

RDF, SPARQL and Linked Data technologies

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case-insensitive

A case-insensitive string for Scala

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catbird

Cats instances for various Twitter Open Source Scala projects

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Cats Collections

Data structures that facilitate pure functional programming with cats

Typelevel member

Cats-Effect

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

Typelevel member

Cats MTL

Monad transformers made easy

Typelevel member

cats-parse

A parsing library for the cats ecosystem

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cats-scalatest

Scalatest bindings for Cats.

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Cats Tagless

A library of utilities for tagless final algebras

Typelevel member

Cats-Time

Instances for Cats Typeclasses for Java 8 Time

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Cats

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

Functional Programming

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Ciris

Functional Configurations for Scala

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coulomb

A statically typed unit analysis library for Scala

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cron4s

Cross-platform CRON expression parsing for Scala

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decline

A composable command-line parser for Scala.

Command-line parsing

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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.

Flexible law checking

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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.

Principled database access

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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”

effects

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Extruder

Populate case classes from any configuration source

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fabric

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

JSON Library

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Fetch

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

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Finch

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

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Frameless

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

Typeful Spark

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fs2-grpc

gRPC implementation for FS2/cats-effect

Typelevel member

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).

Stream Processing

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Hammock

Purely functional HTTP client

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http4s

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

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imp

Summoning implicit values

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jawn-fs2

Integration of jawn and fs2 for streaming, incremental JSON parsing

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keypool

A Keyed Pool Implementation for Scala

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kind-projector

Plugin for nicer type-lambda syntax

Typelevel member

Kittens

Automatic type class derivation

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Libra

Compile time dimensional analysis for any problem domain

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log4cats

Logging Tools For Interaction with cats-effect

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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.

Asynchronous, Reactive Programming

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Monocle

Strongly inspired by Haskell's lens library, Monocle is an Optics library where Optics gather the concepts of Lens, Traversal, Optional, Prism and Iso.

Lenses for Scala

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Mouse

Enrichments to standard library classes to ease functional programming

Typelevel member

otel4s

An OpenTelemetry library based on cats-effect

Typelevel member

Outwatch

The Functional and Reactive Web-Frontend Library for Scala.js

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PureConfig

A boilerplate-free library for loading configuration files

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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.

Constraints on types

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Scala Exercises

Platform and framework for Scala devs to learn about Scala libraries

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scala-steward

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

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scalacheck-shapeless

Automatic derivation for ScalaCheck

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ScalaCheck

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

Property checking

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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.

Binary serialization

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Scoverage

Code coverage tool for Scala

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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.

Generic Programming

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Simulacrum Scalafix

Simulacrum as Scalafix rules

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simulacrum

First-class syntax for type classes

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singleton-ops

Operations for primitive and String singleton types

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sonic

Property-based testing with integrated shrinking

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specs2

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

Expressive specifications

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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.

Numeric abstractions

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Squants

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

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TwoTails

A compiler plugin adding support for mutual tail recursion

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typelevel-nix

Development tools for Typelevel projects

Typelevel member

typelevel.g8

A Giter8 template for sbt-typelevel

Typelevel member

uniform-scala

Functional user journeys

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vault

Type-safe, persistent storage for values of arbitrary types

Typelevel member

Submitting

Are you interested in submitting your library to the Typelevel Ecosystem?

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