Data Formats

• toon-crystal (⭐9) - TOON (Token-Oriented Object Notation) parser

Misc

• cpf_cnpj - Provide utilities for validating and formatting CPF and CNPJ identifiers

Converters

• tssc.cr (⭐6) - Time::Span String Converter (incl. JSON & YAML support)

Project Generators

• crygen (⭐13) - A library that allows to generate the Crystal code

Security

• cyclonedx-cr (⭐4) - CycloneDX SBOM(Software Bill of Materials) generator for Crystal projects

• OWASP Noir (⭐1.1k) - Attack surface detector that identifies endpoints by static analysis

• XSSMaze (⭐30) - XSSMaze is a web service that tests security tools using diverse XSS cases

Data Formats

• jmespath.cr (⭐12) - Crystal implementation of JMESPath, a query language for JSON

Code Analysis and Metrics

• cruml (⭐7) - A tool that provides an UML class diagram generator for any Crystal projects

Network Protocols

• dns (⭐13) - DNS protocol implementation and resolver

HTML/XML Parsing

• lexbor (⭐111) - Fast HTML5 Parser that includes CSS selectors

Misc

• sentry (⭐6) - Build/Runs your crystal application, watches files, and rebuilds/restarts app on file changes.

Official Documentation Translations

• procodile (⭐11) - Run processes in the background (and foreground) on Mac & Linux from a Procfile (for production and/or development environments)

C bindings

• gpio.cr (⭐3) - Bindings for the gpiod library (general purpose IO control and feedback)

Network Protocols

• knx (⭐3) - KNX protocol implementation supporting multicast, unicast and TCP/IP tunnelling

Environment Management

• vfox-crystal (⭐10) - Plugin for vfox version manager

Testing

• selenium.cr (⭐26) - Selenium client for interacting with web pages for browser automation

Unofficial

• Learn X in Y minutes - Quick tutorial on Crystal

• Usability of Programming Languages - Comparison of Python, Rust, Crystal

Markdown/Text Processors

• cr-cmark-gfm (⭐21) - Crystal C bindings for cmark-gfm to work with Commonmark and Github Flavored Markdown

Queues and Messaging

• crafka (⭐20) - Apache Kafka library utilizing librdkafka

Web Frameworks

• Crystal newsletter

• IRC - #crystal-lang on Libera

Algorithms and Data structures

• HKDF (⭐1) - HMAC-based Extract-and-Expand Key Derivation Function rfc5869

• named_information (⭐0) - Naming Things with Hashes rfc6920

• SPAKE2+ (⭐2) - Password Authenticated Key Exchange (PAKE) protocol, comparable to SRP-6a

• verhoeff (⭐0) - Implementation of the Verhoeff checksum algorithm

C bindings

• v4l2.cr (⭐5) - Bindings for Video4Linux2

Game Development

• Raylib-cr (⭐106) - Direct bindings to Raylib, which supports Linux, Windows, and Mac

HTML Builders

• to_html (⭐16) - The fastest HTML builder engine for Crystal

C bindings

• win32cr (⭐19) - Bindings for Win32 API

Unofficial

• Crystal Shards for Ruby Gems (⭐20k) - A list of Ruby Gems and their Crystal Shards equivalents

HTML Builders

• blueprint (⭐74) - Write reusable and testable HTML templates in plain Crystal

C bindings

• crystal-gsl (⭐5) - Bindings for GNU Scientific Library

Implementations/Compilers

• novika (⭐19) - A free-form, moldable, interpreted programming language

CLI Utils

• git-repository (⭐5) - A git cli wrapper querying and cloning remote repositories with minimal data transfer

Editor Plugins

• IntelliJ IDEA
  • intellij-crystal-lang (⭐40) - Crystal support for the JetBrains IDEs

CLI Builders

• Cling (⭐32) - A modular, non-macro-based command line interface library

Database Drivers/Clients

• surrealdb.cr (⭐7) - Unoffical SurrealDB HTTP & Websocket Client

Testing

• hashr (⭐2) - A tiny class makes test on JSON response easier

Official Documentation Translations

• port_ruby_to_crystal (⭐10) - A regex replace ruby script for port ruby code to crystal easier, reduce friction

GUI Development

• Ultimate GTK4 Crystal Guide - Learn how to create premium GTK4 apps in Crystal

Misc

• observable (⭐9) - Implementation of the observer pattern

Editor Plugins

• Lite-XL
  • lite-plugin-crystal (⭐6) - Crystal support for the Lite-XL editor

Image processing

• Pluto (⭐74) - A fast and convenient image processing library

Web Frameworks

• Crystal Forum

CLI Utils

• hetzner-k3s (⭐3.3k) - A CLI tool to quickly create and manage Kubernetes clusters in Hetzner Cloud

Image processing

• ffmpeg (⭐22) - FFmpeg bindings that works with StumpyPNG to extract frames

Third-party APIs

• amazonite (⭐1) - An unofficial SDK supporting popular AWS APIs

Algorithms and Data structures

• Goban (⭐30) - A fast and efficient QR Code implementation

Web Frameworks

• marten (⭐465) - A web framework that makes building web applications easy, productive, and fun

Game Development

• SDL-Crystal-Bindings (⭐15) - Direct (unsafe) bindings to SDL2, intended for writing own game libraries

Cryptography

• ed25519 (⭐11) - the Ed25519 elliptic curve public-key signature system described in [RFC 8032]

Data Formats

• json-schema (⭐15) - convert JSON serializable classes into a JSON Schema representation

GUI Development

• GTK4.cr (⭐121) - Bindings for GTK4 with Crystalized API

Network Protocols

• mqtt-client.cr (⭐5) - A fast and lightweight MQTT client

Algorithms and Data structures

• csuuid (⭐16) - A Chronologically Sortable UUID

• secure-remote-password (⭐7) - SRP-6a protocol for authentication over an insecure network

Logging and monitoring

• fiber_metrics.cr (⭐9) - Track run time, wait time, or memory allocations per Fiber, method or block

Processes and Threads

• concurrent.cr (⭐48) - Simplified concurrency using streams/pipelines, waitgroups, semaphores, smores and more

Misc

• defined (⭐18) - macros for conditional compilation based on constant definitions, version requirements, or environment variable settings

C bindings

• fftw.cr (⭐12) - Bindings for FFTW library

• wasmer-crystal (⭐98) - Bindings for the wasmer WebAssembly runtime

C bindings

• nlopt.cr (⭐3) - Bindings for NLOpt

Cryptography

• monocypher.cr (⭐19) - Crystal wrapper for the Monocypher crypto library

Game Development

• MyECS (⭐21) - A Sparse Entity Component System Framework for Crystal

CLI Builders

• Athena Console (⭐22) - Allows for the creation of CLI based commands

HTML/XML Parsing

• docx_cr_converter (⭐11) - parse DOCX Word

Third-party APIs

• mollie.cr (⭐22) - Mollie Payments API wrapper (Creditcard, PayPal, Apple Pay, Sofort, Klarna, ...)

C bindings

• augeas.cr (⭐8) - Bindings for Augeas

Networking

• mac-address (⭐2) - Library for working with MAC addresses

Internationalization

• Rosetta (⭐58) - A blazing fast internationalization (i18n) library with compile-time key lookup supporting YAML and JSON formats

Internationalization

• Lens (⭐18) - A multiformat internationalization (i18n) shard for Crystal. Supports Gettext, Ruby YAML, etc.

Internationalization

• crystal-i18n (⭐31) - An internationalization library inspired by Ruby-I18n

• i18n.cr (⭐22) - Internationalization shard

Converters

• crunits (⭐6) - Tool for converting units of measure (miles to kilometers, celsius to fahrenheit etc)

Network Protocols

• crystal-bacnet (⭐0) - BACnet protocol implementation with BACnet/IP client

Third-party APIs

• tmdb.cr (⭐4) - The Movie DB (TMDb) api wrapper

Network Protocols

• simple_rpc (⭐70) - RPC Server and Client for Crystal. Implements msgpack-rpc protocol

CLI Utils

• meet (⭐42) - Start a jitsi meeting quickly from the comfort of your command line

Algorithms and Data structures

• crystalg (⭐38) - A Generic Algorithm Library

CLI Utils

• oq (⭐204) - A performant, and portable jq wrapper to facilitate the consumption and output of formats other than JSON; using jq (⭐34k) filters to transform the data

Dependency Injection

• HardWire (⭐23) - A compile-time non-intrusive dependency injection system

Framework Components

• mochi (⭐26) - Authentication shard inspired by Devise supporting: Authenticable, Confirmable, Invitable & more

• motion.cr (⭐55) - Object oriented frontend library for Amber

• tourmaline (⭐167) - Telegram bot framework with an API loosely based on telegraf.js

Misc

• burocracia.cr (⭐23) - burocracia.cr the dependecyless shard to validate, generate and format Brazilian burocracias such as CPF, CNPJ and CEP

ORM/ODM Extensions

• avram (⭐176) - A database wrapper for reading, writing, and migrating Postgres databases

Queues and Messaging

• mosquito (⭐237) - Redis backed periodic and ad hoc job processing

Serverless Computing

• secrets-env (⭐6) - Extends ENV module to read values injected by docker / kubernetes secrets and other orchestration tools

Editor Plugins

• Geany
  • geany-crystal (⭐9) - Crystal support for the Geany editor

LSP Language Server Protocol Implementations

• crystalline (⭐510) - Crystalline is an implementation of the Language Server Protocol written in and for the Crystal Language

Compression

• Gzip - readers and writers of gzip format (Crystal stdlib)

• Zip - readers and writers of zip format (Crystal stdlib)

• Zlib - readers and writers of zlib format (Crystal stdlib)

CLI Utils

• coin (⭐7) - Command-line application that performs currency conversion via the Fixer API

Algorithms and Data structures

• splay_tree_map (⭐16) - Splay Tree implementation that conforms to the Hash ducktype

Debugging

• backtracer.cr (⭐18) - Shard aiming to assist with parsing backtraces into a structured form

• debug.cr (⭐103) - debug!(…) macro for pp-style debugging

Misc

• serf-handler.cr (⭐1) - Framework for building Serf handlers, with a suite of useful builtin capabilities

Network Protocols

• stomp (⭐1) - STOMP protocol

Algorithms and Data structures

• s2_cells (⭐0) - S2 Geometry for spatial indexing

HTTP

• link-header (⭐1) - HTTP Link Header Parser

Editor Plugins

• Acme:
  • acmecrystal (⭐6) - Reformats crystal code in acme

• Emacs
  • crystal-mode - Crystal language support for Emacs (crystal-lang-tools/emacs-crystal-mode (⭐52))

Misc

• anyolite (⭐177) - Full mruby interpreter with simple bindings, allowing for easy scripting support in projects

Framework Components

• Athena Negotiation (⭐5) - Framework agnostic content negotiation library

Testing

• Athena Spec (⭐3) - Common/helpful Spec compliant testing utilities

LSP Language Server Protocol Implementations

• scry (⭐331) - Code analysis server for Crystal implementing the Language Server Protocol

Algorithms and Data structures

• qr-code (⭐23) - QR Code generator

Image processing

• celestine (⭐95) - Create SVG images using a DSL

Data Formats

• Crystalizer (⭐41) - (De)serialize any Crystal object; supporting JSON, YAML, and Byte formats out of the box

Blockchain

• Axentro (⭐195) - A custom blockchain platform

Validation

• Athena Validator (⭐7) - Robust & flexible validation framework

Official Documentation Translations

• Invidious (⭐19k) - Invidious is an alternative front-end to YouTube

Misc

• sslscan.cr (⭐10) - Crystal shard wrapping the rbsec/sslscan utility

Processes and Threads

• werk (⭐30) - Dead simple task runner with concurrent support, ideal for local CI

Network Protocols

• mDNS (⭐8) - DNS Service Discovery and multicast DNS

Configuration

• Envy (⭐10) - Load environment variables from YAML

Web Frameworks

• grip (⭐292) - The microframework for writing powerful web applications

Compression

• polylines.cr (⭐10) — compression of series of coordinates

Framework Components

• Shield (⭐55) - Comprehensive security for Lucky framework

Misc

• wafalyzer (⭐35) - Web Application Firewall (WAF) Detector - shard + cli

Game Development

• crystal-chipmunk (⭐44) - Bindings to Chipmunk, a fast and lightweight 2D game physics library

• crystal-imgui-sfml (⭐18) - Bindings to integrate Dear ImGui (⭐71k) into an SFML project

GUI Development

• crystal-imgui (⭐76) - Bindings to Dear ImGui (⭐71k), an immediate-mode graphical UI library

HTTP

• ntlm (⭐4) - NTLM authentication

GUI Development

• Iu (⭐76) - UI framework based on the Fusion/libui.cr (⭐182) library, with custom elements and modified bindings from hedron-crystal/hedron (⭐87)

HTTP

• digest-auth (⭐4) - Digest authentication

Framework Components

• graphql (⭐138) - Type-safe GraphQL server implementation

• graphql-crystal (⭐213) - GraphQL implementation

Unofficial

• crystal-koans (⭐53) - Learn Crystal by writing unit tests

Database Drivers/Clients

• cryomongo (⭐78) - MongoDB driver

Misc

• version_tools (⭐9) - Version-dependent behaviour, specified at compile-time

Science and Data analysis

• alea (⭐12) - Repeatable sampling, CDF and other utilities to work with probability distributions

CLI Utils

• climate (⭐17) - Tiny tool to make your CLI output 🌈 coloured

CLI Utils

• lff (⭐19) - Simple and straightforward large files finder utility in command line

Database Drivers/Clients

• crystal-ldap (⭐19) - LDAP client

Network Protocols

• crystal-mqtt (⭐21) - A MQTT client

Dependency Injection

• Athena Dependency Injection (⭐11) - Robust dependency injection service container framework

Framework Components

• Athena Event Dispatcher (⭐15) - A Mediator and Observer pattern event library

Web Frameworks

• Athena (⭐226) - A web framework comprised of reusable, independent components

Official Documentation Translations

• Crank (⭐52) - A Procfile-based application manager (like Foreman)

Code Analysis and Metrics

• linguist.cr (⭐11) - Using multiple ways to find programming language used in files, based on Github's Linguist

Misc

• simple_retry (⭐7) - Simple tool for retrying failed code blocks

Third-party APIs

• stripe.cr (⭐52) - Stripe api wrapper

Web Frameworks

• runcobo (⭐50) - An api framework with simple, intuitive and consistent DSL, using jbuilder to render json

Algorithms and Data structures

• blurhash.cr (⭐26) - BlurHash (⭐17k) implementation

Email

• sendgrid.cr (⭐16) - Simple Sendgrid Client

Environment Management

• crenv (⭐238) - Crystal version manager

Game Development

• entitas.cr (⭐38) - A Entity Component System Framework for Crystal

Science and Data analysis

• quartz (⭐16) - Modeling and simulation framework

Misc

• gphoto2-web.cr (⭐13) - Web API for libgphoto2

Logging and monitoring

• Log - logging utility (Crystal stdlib)

CLI Builders

• Keimeno (⭐16) - A lightweight text user interface library in Crystal

Third-party APIs

• google (⭐25) - Google API wrapper

• office365 (⭐11) - Microsoft Graph API wrapper

Data Generators

• prime (⭐2) - A prime number generator

Machine Learning

• mxnet.cr (⭐22) - Bindings for MXNet

Misc

• iterm2 (⭐6) - Display images within the terminal using the ITerm2 Inline Images Protocol

Science and Data analysis

• ishi (⭐48) - Graph plotting package with a small API and sensible defaults powered by gnuplot

Third-party APIs

• host_meta (⭐3) - A Web Host Metadata (https://tools.ietf.org/html/rfc6415) client

• web_finger (⭐9) - A WebFinger (https://tools.ietf.org/html/rfc7033) client

Official Documentation Translations

• public_suffix (⭐2) - A small library designed to make the Public Suffix List (https://publicsuffix.org/) easier to use

Network Protocols

• amqp-client.cr (⭐72) - AMQP 0-9.1, a messaging protocol, implemented by eg. RabbitMQ

Web Frameworks

• Shivneri (⭐23) - Component based MVC web framework for crystal targeting good code structures, modularity & performance

Validation

• validator (⭐30) - Data check and validation

Unofficial

• Portuguese-speaking Telegram Group - Bem vindos ao Crystal Brasil!

Algorithms and Data structures

• fzy (⭐47) - A Crystal port of awesome Fzy project fuzzy finder algorithm

HTML Builders

• Water (⭐30) - A library for writing HTML in plain Crystal

Cryptography

• cmac (⭐5) - Crystal implementation of Cipher-based Message Authentication Code (CMAC)

Blockchain

• Cocol (⭐20) - A minimal blockchain testbed

• secp256k1.cr (⭐51) - Elliptic curve used in the public-private-key cryptography

Shell plugins

• crystal-zsh (⭐27) - .oh-my-zsh plugin

Data Formats

• JSON::OnSteroids (⭐25) - handle and mutate JSON document easily

Algorithms and Data structures

• haversine (⭐19) - An Implementation of the Haversine formula

• kd_tree (⭐19) - An implementation of "K-Dimensional Tree" and "N-Nearest Neighbors"

Machine Learning

• Cadmium (⭐209) - NLP library based heavily on natural (⭐11k)

Misc

• CrSignals (⭐10) - Signals/slots notification library

Data Formats

• HAR (⭐22) - HAR (HTTP Archive) parser

Science and Data analysis

• num.cr (⭐160) - Numerical computing library supporting N-Dimensional data

Framework Components

• shrine.cr (⭐81) - File Attachment toolkit for Crystal applications. Heavily inspired by Shrine for Ruby

Unofficial

• Crystal Programming Discord Server - Unofficial Discord server dedicated to the Crystal Programming Language

Template Engine

• Jbuilder (⭐44) - Generate JSON objects with a Builder-style DSL, inspired by jbuilder

C bindings

• clang.cr (⭐50) - Libclang bindings

CLI Builders

• Phreak (⭐34) - A highly flexible Crystal CLI builder in the style of OptionParser

Dependency Injection

• Crystal-DI (⭐33) - Lightweight DI Container

• syringe (⭐8) - A simple and basic dependency injection shard for crystal

HTTP

• proxy-fetcher.cr (⭐11) - Proxy lists fetching & validating library

Compression

• Crystar (⭐47) - Readers and writers of Tar archive format

• snappy (⭐22) - Snappy compression format reader/writer for Crystal

• zstd.cr (⭐42) - Bindings for Zstandard (⭐27k) compression library

ORM/ODM Extensions

• crecto (⭐349) - Database wrapper, based on Ecto

Algorithms and Data structures

• crie (⭐12) - Compile-time Trie

Network Protocols

• connect-proxy (⭐7) - Connect method style of HTTP tunnelling / HTTP proxy

CLI Utils

• tablo (⭐37) - A flexible terminal table generator

Misc

• zaru_crystal (⭐13) - Filename sanitization

Network Protocols

• telnet.cr (⭐11) - Telnet protocol

Network Protocols

• Crirc (⭐21) - IRC protocol implementation (Client, Server, Bots)

Network Protocols

• cr-xmpp (⭐17) - XMPP/Jabber Library

Queues and Messaging

• NATS.io (⭐44) - NATS client

Third-party APIs

• crystal-consul (⭐19) - Consul API client

Code Analysis and Metrics

• ameba (⭐552) - A static code analysis tool

HTTP

• Cable (⭐131) - An ActionCable "port" to Crystal, framework agnostic, 100% compatible with the ActionCable JS Client

Logging and monitoring

• crafana (⭐21) - A Grafana library to help autogenerate dashboards

Misc

• monads (⭐47) - Monad implementation

Testing

• vcr (⭐59) - A HTTP capture and replay implementation for crystal

Third-party APIs

• kube-client.cr (⭐22) - Kubernetes API Client

Cryptography

• sodium.cr (⭐51) - Crystal wrapper for the libsodium crypto API

HTTP

• sse.cr (⭐25) - Server-Sent Events client

Misc

• pinger (⭐11) - Ping IP addresses and DNS entries without requiring sudo

Third-party APIs

• ynab.cr (⭐4) - A library to interact with your YNAB data

Testing

• spectator - Feature rich spec framework that uses the modern expect syntax

Misc

• port_midi (⭐7) - Crystal C bindings for the PortMIDI cross-platform MIDI I/O library

Network Protocols

• crystal-snmp (⭐17) - An SNMP implementation with version 1, 2c and 3 support

C bindings

• crystal-hunspell (⭐8) - Bindings for Hunspell

Misc

• crystal-web-framework-stars (⭐74) - Web frameworks for Crystal, most starred on Github

ORM/ODM Extensions

• rethinkdb-orm (⭐24) - ORM for RethinkDB / RebirthDB

CLI Utils

• tallboy (⭐61) - Generate ASCII character tables with support for spanning cells over multiple columns

HTML Builders

• form_builder.cr (⭐33) - Dead simple HTML form builder for Crystal with built-in support for many popular UI libraries such as Bootstrap

Data Formats

• BinData (⭐48) - Binary data parser helper with an ASN.1 parser

Email

• CrystalEmail - A RFC compliant Email validator

Network Protocols

• transfer_more - Clone of transfer.sh to uploads files

C bindings

• ssh2.cr (⭐48) - Bindings for libssh2 library

HTTP

• http-params-serializable (⭐21) - HTTP params (de)serialization, applicable to URL queries and URL-encoded forms

Testing

• webdriver_pump (⭐5) - Page Object library. Inspired by Ruby's WatirPump (⭐16)

Database Drivers/Clients

• crystal-rethinkdb (⭐22) - Driver for RethinkDB / RebirthDB

Data Formats

• geoip2.cr (⭐20) - GeoIP2 reader

• maxminddb.cr (⭐27) - MaxMindDB reader

Examples and funny stuff

• blackjack-cr (⭐10) - Console Blackjack

Algorithms and Data structures

• graphlb (⭐21) - Collection of graph datastructure and algorithms

Testing

• crytic (⭐68) - Mutation testing framework

Framework Components

• praetorian (⭐61) - Minimalist authorization library inspired by Pundit

Testing

• timecop.cr (⭐21) - Library for mocking with Time.now. Inspired by the timecop ruby gem (⭐3.4k)

Official Documentation Translations

• ast_helper (⭐25) - Helper tool to debug parser and formatter

Database Drivers/Clients

• couchdb.cr (⭐14) - CouchDB client

Serverless Computing

• crystal_openfaas (⭐23) - Template to enable crystal as first class citizens in OpenFaaS

Official Documentation Translations

• shards.info - Web service that lists all repositories on GitHub that have Crystal code in them. The sources are available on GitHub (⭐43)

Data Formats

• toml.cr (⭐65) - TOML parser

Unofficial

• Crystal for Rubyists - Free book to bootstrap your Crystal journey

• Programming Crystal - PragProg book to start your Crystal journey

Examples and funny stuff

• crystalworld (⭐43) - realworld.io back-end API implementation

Validation

• accord (⭐26) - Shareable validation library for Crystal Objects

• validations (⭐13) - Validations mixin

Configuration

• envyable (⭐7) - A simple YAML to ENV config loader

Misc

• callbacks (⭐12) - Expressive callbacks module

Official Documentation Translations

• quicktype - Generate models and serializers from JSON, JSON Schema, GraphQL, and TypeScript

Algorithms and Data structures

• CrOTP (⭐66) - HOTP and TOTP implementation for two factor authentication

Misc

• retriable.cr (⭐45) - Simple DSL to retry failed code blocks

DevOps

• DPPM (⭐119) - An easy, universal way to install and manage applications as packages (mostly Linux)

Algorithms and Data structures

• ksuid.cr (⭐17) - K-Sortable Globally Unique IDs

C bindings

• syslog.cr (⭐11) - Bindings for syslog

Algorithms and Data structures

• bisect (⭐12) - Inserting values into a sorted array

Processes and Threads

• promise (⭐43) - A Promise implementation with type inference

Scheduling

• tasker (⭐56) - A high precision scheduler including timezone aware cron jobs

Shell plugins

• crun (⭐47) - Crystal Run : shebang wrapper for Crystal

Configuration

• totem (⭐72) - Load and parse a configuration in JSON, YAML, dotenv formats

Processes and Threads

• await_async (⭐87) - Add keywords await & async in Crystal Lang

Network Protocols

• crystal-json-socket (⭐14) - JSON-socket client & server implementation. Inspired by and compatible with node-json-socket (⭐155) and ruby-json-socket (⭐4)

Converters

• base62.cr (⭐13) - Base62 encoder/decoder, well suited for url-shortening

CLI Utils

• cride (⭐54) - A light CLI text editor/IDE

Implementations/Compilers

• LinCAS-lang - A programming language for scientific computation

Framework Components

• Exception Page (⭐72) - An exceptional exception page for Crystal web libraries and frameworks

Testing

• mass-spec (⭐9) - Web API testing library

CLI Builders

• clicr (⭐31) - A simple declarative command line interface builder

Converters

• money (⭐43) - Handling money and currency conversion with ease (almost complete port of RubyMoney (⭐2.8k))

Unofficial

• Russian-speaking Telegram Group - Добро пожаловать, товарищ!

Framework Components

• device_detector (⭐23) - Shard for detect device by user agent string

Official Documentation Translations

• mpngin (⭐35) - A URL shortener with simple stats

Scheduling

• crystime - Advanced time, calendar, schedule, and remind library

Data Formats

• config.cr (⭐14) - Easy to use configuration format parser

• front_matter.cr (⭐13) - Separates a files front matter from its content

Testing

• LuckyFlow (⭐54) - Automated browser tests similar to Capybara

System

• baked_file_system (⭐187) - Virtual file system implementation

• hardware (⭐76) - Get CPU, Memory and Network informations of the running OS and its processes

Implementations/Compilers

• mint-lang (⭐4.2k) - A refreshing programming language for the front-end web

• runic-lang - In-design toy language

ORM/ODM Extensions

• granite (⭐308) - ORM for Postgres, Mysql, Sqlite

Email

• carbon (⭐86) - Fun, testable, and adapter-based email library

Data Formats

• crinder (⭐28) - Class based json renderer

HTTP

• halite (⭐171) - Crystal HTTP Requests with a chainable REST API, built-in sessions and loggers

CLI Builders

• OptionParser - command-line options processing (Crystal stdlib)

Data Formats

• CSV - parsing and generating for comma-separated values (Crystal stdlib)

• INI - INI file parser (Crystal stdlib)

• JSON - parsing and generating JSON documents (Crystal stdlib)

• XML - parsing and generating XML documents (Crystal stdlib)

• YAML - parsing and generating YAML documents (Crystal stdlib)

HTTP

• HTTP::Client - HTTP client (Crystal stdlib)

• HTTP::Server - HTTP server (Crystal stdlib)

• HTTP::WebSocket - HTTP WebSocket client (Crystal stdlib)

Network Protocols

• OAuth - OAuth consumer (Crystal stdlib)

• OAuth2 - OAuth2 client (Crystal stdlib)

• OpenSSL - bindings to libssl (Crystal stdlib)

Networking

• ipaddress.cr (⭐45) - Library to handle IPv4 and IPv6 addresses

Template Engine

• ECR (Embedded Crystal) - compile time template language which uses plain crystal expressions (Crystal stdlib)

Testing

• Spec - spec framework (Crystal stdlib)

Third-party APIs

• twitter-crystal (⭐82) - A library to access the Twitter API

Web Frameworks

• spider-gazelle (⭐188) - A Rails esque web framework with a focus on speed and extensibility

C bindings

• pledge.cr (⭐10) - Bindings for OpenBSD's pledge(2)

C bindings

• x_do.cr (⭐16) - Bindings for libxdo (xdotool)

Routing

• orion (⭐128) - A minimal, rails-esque routing library

Database Tools

• migrate (⭐32) - A simpler database migration tool with transactions

Official Documentation Translations

• cry (⭐34) - Ability to execute crystal code in a fashion similar to Ruby's pry edit

Machine Learning

• shainet (⭐194) - SHAInet (Neural Network in pure crystal)

ORM/ODM Extensions

• clear (⭐280) - ORM specialized to PostgreSQL only but with advanced features

Unofficial

• devdocs.io - API Documentation Browser with Crystal support

Configuration

• habitat (⭐83) - Type safe configuration for your classes and modules

Web Frameworks

• lucky (⭐2.7k) - Catch bugs early, forget about most performance issues, and spend more time on code instead of debugging and writing tests

HTTP

• crest (⭐246) - Simple HTTP and REST client, inspired by the Ruby's RestClient gem

DevOps

• ansible-crystal (⭐9) - Ansible playbook for installing crystal

Third-party APIs

• GDAX (⭐7) - GDAX REST and WebSocket API Wrapper with request signing

Third-party APIs

• mixpanel-crystal (⭐0) - A library for sending events to Mixpanel

Algorithms and Data structures

• markov (⭐20) - Build Markov Chains and run Markov Processes

Machine Learning

• ai4cr (⭐28) - Artificial Intelligence (based on https://github.com/SergioFierens/ai4r (⭐720))

Examples and funny stuff

• crystal-patterns (⭐303) - Examples of GOF patters

Markdown/Text Processors

• markd (⭐122) - Yet another markdown parser built for speed, Compliant to CommonMark specification

Machine Learning

• crystal-fann (⭐87) - FANN (Fast Artifical Neural Network) binding

Web Frameworks

• amber (⭐2.6k) - Open source efficient and cohesive web application framework

HTTP

• http-multiserver.cr (⭐24) - Mounting multiple servers via routes (a.k.a. URL mapping)

Official Documentation Translations

• crystal-base (⭐2) - CentOS base docker image for Crystal development

Database Drivers/Clients

• leveldb (⭐41) - Crystal bindings for LevelDB

Examples and funny stuff

• exercism-crystal (⭐79) - Exercism exercises

Game Development

• CrSFML (⭐354) - Bindings to SFML multimedia/game library

HTTP

• cossack (⭐110) - Simple flexible HTTP client

Image processing

• stumpy_png (⭐108) - Read and write PNG images

Network Protocols

• jwt (⭐211) - Implementation of JWT (JSON Web Token)

• msgpack-crystal (⭐146) - MessagePack library

Package Management

• shards (⭐790) - Dependency manager for the Crystal

Web Frameworks

• kemal (⭐3.8k) - Lightning Fast, Super Simple web framework. Inspired by Sinatra

• Reddit

• Stackoverflow

Unofficial

• crystal-lang.org - Official language site

Official Documentation Translations

• icr (⭐507) - Interactive console for Crystal (like IRB for Ruby)

Editor Plugins

• Sublime
  • sublime-crystal (⭐88) - Crystal syntax highlighting for sublime Text

• TextMate
  • Crystal.tmbundle (⭐19) - Crystal syntax highlighting, compile, format command, snippets

• Vim
  • vim-crystal (⭐425) - Vim filetype support for Crystal
  • vim-slang (⭐13) - Vim filetype support for Slang Templating Engine

• Visual Studio Code
  • vscode-crystal-lang (⭐300) - Formatter, linter and syntax highlighting for cr and ecr files

Testing

• microtest (⭐32) - Small opinionated testing library focusing on power asserts

ORM/ODM Extensions

• jennifer.cr (⭐425) - Active Record pattern implementation with flexible query chainable builder and migration system

Implementations/Compilers

• myst-lang - A practical, dynamic language designed to be written and understood as easily and efficiently as possible

Third-party APIs

• pinboard.cr (⭐7) - Pinboard API

Third-party APIs

• awscr-s3 (⭐88) - AWS S3 interface

Converters

• sass.cr (⭐38) - Compile SASS/SCSS to CSS (libsass (⭐4.3k) binding)

Email

• crystal-email (⭐115) - Simple e-mail sending library

Science and Data analysis

• linalg (⭐52) - Linear algebra library inspired by MATLAB and SciPy.linalg

CLI Utils

• progress_bar.cr (⭐17) - A simple and customizable progress bar

Template Engine

• crinja (⭐140) - An implementation of the Jinja2 template engine

Framework Components

• multi-auth (⭐116) - Standardized multi-provider OAuth2 authentication (inspired by omniauth)

Scheduling

• schedule.cr (⭐76) - Run periodic tasks

CLI Builders

• clim (⭐125) - Slim command line interface builder

C bindings

• icu.cr (⭐14) - Bindings for the ICU library

Project Generators

• libgen (⭐83) - Automatic bindings generator configured using JSON/YAML files

Task management

• cake (⭐73) - Production-ready Make-like utility tool

Implementations/Compilers

• cltk (⭐72) - A crystal port of the Ruby Language Toolkit

Routing

• router.cr (⭐270) - Minimum but powerful http router for HTTP::Server

C bindings

• crt.cr (⭐27) - Bindings for libncursesw and crt

• duktape.cr (⭐141) - Bindings for the Duktape (⭐6.2k) javascript engine

• gphoto2.cr (⭐19) - Bindings for the libgphoto2 library

• libnotify.cr (⭐26) - Bindings for Libnotify

• pcap.cr (⭐26) - Bindings for libpcap

Logging and monitoring

• statsd.cr (⭐36) - Statsd (⭐18k) client library

Processes and Threads

• neph (⭐205) - A modern command line job processor that can execute jobs concurrently

Official Documentation Translations

• crystal-dash-docset (⭐19) - Dash docset generator

Misc

• crz (⭐94) - Functional programming library

Framework Components

• kemal-session (⭐62) - Session handler for Kemal

Third-party APIs

• crystal-darksky (⭐8) - Wrapper for the Dark Sky API

Third-party APIs

• crystal-swapi (⭐5) - Star Wars API (SWAPI) wrapper

Search

• hermes (⭐38) - Data Mapper pattern implementation for ElastiSearch

Task management

• sam (⭐97) - Another one Rake-like task manager with namespacing and arguments system

HTTP

• http-protection (⭐75) - Protection against typical web attacks

Third-party APIs

• raven.cr (⭐128) - Raven is a client for Sentry (⭐43k)

Official Documentation Translations

• kr.crystal-lang.org - Korean

Misc

• any_hash.cr (⭐38) - Recursive Hash with better JSON::Any included

Implementations/Compilers

• charly - Charly Programming Language

CLI Builders

• admiral (⭐140) - A robust DSL for writing command line interfaces

Environment Management

• asdf-crystal (⭐76) - Plugin for asdf version manager

Third-party APIs

• awscr-signer (⭐23) - Sign HTTP::Request objects and generate presigned post forms

Misc

• crystal-binary_parser (⭐20) - Binary parser

Science and Data analysis

• predict.cr (⭐19) - Satellite prediction library using the sgp4 model

Database Drivers/Clients

• rocksdb.cr (⭐40) - RocksDB client

Examples and funny stuff

• try.cr (⭐26) - Try monad

Database Drivers/Clients

• crystal-mysql (⭐111) - MySQL connector for Crystal

• crystal-sqlite3 (⭐154) - SQLite3 bindings

Editor Plugins

• Spacemacs
  • crystal-spacemacs-layer (⭐12) - Spacemacs contribution layer for Crystal

Template Engine

• teeplate (⭐17) - A library for rendering multiple template files

Algorithms and Data structures

• crystal-linked-list (⭐12) - Implementation of Linked List

Project Generators

• crystal_lib (⭐140) - Automatic binding generator for native libraries

Template Engine

• Kilt (⭐152) - Abstraction layer for template engines

• Slang (⭐238) - Lightweight, terse, templating language inspired by Ruby's Slim

Configuration

• cr-dotenv (⭐98) - Loads .env file

Web Frameworks

• Gitter

Data Generators

• hashids.cr (⭐53) - A library to generate YouTube-like ids from one or many numbers

Project Generators

• fez (⭐51) - A Kemal application generator

Network Protocols

• fast_irc.cr (⭐24) - Fast IRC parser/generator

Database Drivers/Clients

• crystal-db (⭐311) - Common db api

Environment Management

• rcm.cr (⭐45) - Redis Cluster Manager

Third-party APIs

• gitlab.cr (⭐30) - GitLab API wrapper

Official Documentation Translations

• br.crystal-lang.org - Brazilian

• ja.crystal-lang.org - Japanese

• ru.crystal-lang.org - Russian

• tw.crystal-lang.org - Chinese Traditional

Algorithms and Data structures

• edits.cr (⭐17) - Collection of edit distance algorithms

Algorithms and Data structures

• crystaledge (⭐27) - A pure Vector Math library

Third-party APIs

• aws-signer.cr (⭐13) - This library signs your HTTP requests using AWS v4

CLI Builders

• commander (⭐128) - Command-line interface builder

Misc

• circuit_breaker (⭐27) - Implementation of the circuit breaker pattern

Queues and Messaging

• sidekiq.cr (⭐775) - Simple, efficient job processing

Algorithms and Data structures

• crystalline (⭐128) - A collection of containers and algorithms

• multiset.cr (⭐4) - Implementation of a multiset

• radix (⭐106) - Radix Tree implementation

HTTP

• http2 (⭐104) - HTTP/2 Protocol Implementation

Template Engine

• crustache (⭐86) - {{Mustache}} for Crystal

Misc

• immutable (⭐203) - Implementation of thread-safe, persistent, immutable collections

Testing

• crotest (⭐28) - A tiny and simple test framework

Implementations/Compilers

• crisp (⭐47) - Lisp dialect implemented with Crystal

Misc

• aasm.cr (⭐54) - Easy to use finite state machine for Crystal classes

Official Documentation Translations

• carc.in - A web service that runs your code and displays the result

Data Generators

• faker (⭐155) - A library for generating fake data

Database Drivers/Clients

• crystal-redis (⭐378) - Full featured Redis client

Misc

• emoji.cr (⭐51) - Emoji library

Testing

• minitest.cr (⭐150) - Library for unit tests and assertions

Testing

• mocks.cr (⭐55) - Mocking library for Crystal

Official Documentation Translations

• DeBot (⭐36) - IRC bot written in Crystal

Caching

• crystal-memcached (⭐36) - Implementation of a memcached client

Database Drivers/Clients

• crystal-pg (⭐478) - A Postgres driver

HTTP

• crul (⭐113) - Command line HTTP client

Testing

• webmock.cr (⭐107) - Library for stubbing HTTP::Client requests

Third-party APIs

• crystal_slack (⭐19) - A tool that parses Slack slash commands or send incoming web hooks

Editor Plugins

• Atom
  • crystal-tools - Enables built in tools in Crystal compiler
  • language-crystal-actual - Crystal language support in Atom