awesome-crystal

Awesome Crystal

A curated list of awesome Crystal code and resources. Inspired by awesome and awesome-awesomeness. The goal is to have projects mostly stable and useful for the community.

Search shards at shards.info for more.

Contributions are welcome. Please take a quick look at the contribution guidelines first.

• Awesome Crystal
  • Algorithms and Data structures
  • Blockchain
  • C Bindings
  • Caching
  • CLI Builders
  • CLI Utils
  • Code Analysis and Metrics
  • Compression
  • Configuration
  • Converters
  • Cryptography
  • Data Formats
  • Data Generators
  • Database Drivers/Clients
  • Database Tools
  • Debugging
  • Dependency Injection
  • Email
  • Environment Management
  • Examples and funny stuff
  • Framework Components
  • Game Development
  • GUI Development
  • HTML Builders
  • HTML/XML parsing
  • HTTP
  • Image Processing
  • Implementations/Compilers
  • Internationalization
  • Logging and monitoring
  • Machine Learning
  • Markdown/Text Processors
  • Misc
  • Network Protocols
  • Networking
  • ORM/ODM Extensions
  • Package Management
  • Processes and Threads
  • Project Generators
  • Queues and Messaging
  • Routing
  • Scheduling
  • Science and Data analysis
  • Search
  • Security
  • Serverless Computing
  • System
  • Task management
  • Template Engine
  • Testing
  • Third-party APIs
  • TUI
  • Validation
  • Web Frameworks
• Community
  • Unofficial
• Resources
  • Official Documentation Translations
• Services and Apps
• Tools
  • DevOps
  • Editor Plugins
  • LSP Language Server Protocol Implementations
  • Shell Plugins

Algorithms and Data structures

• bisect - Inserting values into a sorted array
• blurhash.cr - BlurHash implementation
• crie - Compile-time Trie
• CrOTP - HOTP and TOTP implementation for two factor authentication
• crystal-linked-list - Implementation of Linked List
• crystaledge - A pure Vector Math library
• crystalg - A Generic Algorithm Library
• crystalline - A collection of containers and algorithms
• csuuid - A Chronologically Sortable UUID
• edits.cr - Collection of edit distance algorithms
• fzy - A Crystal port of awesome Fzy project fuzzy finder algorithm
• Goban - A fast and efficient QR Code implementation
• graphlb - Collection of graph datastructure and algorithms
• haversine - An Implementation of the Haversine formula
• HKDF - HMAC-based Extract-and-Expand Key Derivation Function rfc5869
• kd_tree - An implementation of “K-Dimensional Tree” and “N-Nearest Neighbors”
• ksuid.cr - K-Sortable Globally Unique IDs
• markov - Build Markov Chains and run Markov Processes
• multiset.cr - Implementation of a multiset
• named_information - Naming Things with Hashes rfc6920
• qr-code - QR Code generator
• radix - Radix Tree implementation
• s2_cells - S2 Geometry for spatial indexing
• secure-remote-password - SRP-6a protocol for authentication over an insecure network
• SPAKE2+ - Password Authenticated Key Exchange (PAKE) protocol, comparable to SRP-6a
• splay_tree_map - Splay Tree implementation that conforms to the Hash ducktype
• verhoeff - Implementation of the Verhoeff checksum algorithm

Blockchain

• Axentro - A custom blockchain platform
• Cocol - A minimal blockchain testbed
• secp256k1.cr - Elliptic curve used in the public-private-key cryptography

C bindings

• augeas.cr - Bindings for Augeas
• clang.cr - Libclang bindings
• crt.cr - Bindings for libncursesw and crt
• crystal-gsl - Bindings for GNU Scientific Library
• crystal-hunspell - Bindings for Hunspell
• duktape.cr - Bindings for the Duktape javascript engine
• fftw.cr - Bindings for FFTW library
• gphoto2.cr - Bindings for the libgphoto2 library
• gpio.cr - Bindings for the gpiod library (general purpose IO control and feedback)
• icu.cr - Bindings for the ICU library
• libnotify.cr - Bindings for Libnotify
• nlopt.cr - Bindings for NLOpt
• pcap.cr - Bindings for libpcap
• pledge.cr - Bindings for OpenBSD’s pledge(2)
• ssh2.cr - Bindings for libssh2 library
• syslog.cr - Bindings for syslog
• v4l2.cr - Bindings for Video4Linux2
• wasmer-crystal - Bindings for the wasmer WebAssembly runtime
• wgpu-cr - Bindings for wgpu-native (WebGPU)
• win32cr - Bindings for Win32 API
• x_do.cr - Bindings for libxdo (xdotool)

Caching

• apt-larder - An HTTP caching proxy for APT package repositories
• cache - A key/value store where pairs can expire after a specified interval
• crystal-memcached - Implementation of a memcached client

CLI Builders

• admiral - A robust DSL for writing command line interfaces
• Athena Console - Allows for the creation of CLI based commands
• clicr - A simple declarative command line interface builder
• clim - Slim command line interface builder
• Cling - A modular, non-macro-based command line interface library
• commander - Command-line interface builder
• Keimeno - A lightweight text user interface library in Crystal
• OptionParser - command-line options processing (Crystal stdlib)
• Phreak - A highly flexible Crystal CLI builder in the style of OptionParser

CLI Utils

• climate - Tiny tool to make your CLI output 🌈 coloured
• coin - Command-line application that performs currency conversion via the Fixer API
• cride - A light CLI text editor/IDE
• git-repository - A git cli wrapper querying and cloning remote repositories with minimal data transfer
• hetzner-k3s - A CLI tool to quickly create and manage Kubernetes clusters in Hetzner Cloud
• lff - Simple and straightforward large files finder utility in command line
• meet - Start a jitsi meeting quickly from the comfort of your command line
• oq - A performant, and portable jq wrapper to facilitate the consumption and output of formats other than JSON; using jq filters to transform the data
• progress_bar.cr - A simple and customizable progress bar
• tablo - A flexible terminal table generator
• tallboy - Generate ASCII character tables with support for spanning cells over multiple columns

Code Analysis and Metrics

• ameba - A static code analysis tool
• cruml - A tool that provides an UML class diagram generator for any Crystal projects
• linguist.cr - Using multiple ways to find programming language used in files, based on Github’s Linguist

Compression

• Crystar - Readers and writers of Tar archive format
• Gzip - readers and writers of gzip format (Crystal stdlib)
• polylines.cr — compression of series of coordinates
• snappy - Snappy compression format reader/writer for Crystal
• Zip - readers and writers of zip format (Crystal stdlib)
• Zlib - readers and writers of zlib format (Crystal stdlib)
• zstd.cr - Bindings for Zstandard compression library

Configuration

• cr-dotenv - Loads .env file
• Envy - Load environment variables from YAML
• envyable - A simple YAML to ENV config loader
• habitat - Type safe configuration for your classes and modules
• totem - Load and parse a configuration in JSON, YAML, dotenv formats
• typed_env_config - Load type-safe configuration from YAML/dotenv with ENV overrides
• ucl.cr - Bindings to libucl, load, dump and validate UCL/JSON configuration

Converters

• base62.cr - Base62 encoder/decoder, well suited for url-shortening
• crunits - Tool for converting units of measure (miles to kilometers, celsius to fahrenheit etc)
• money - Handling money and currency conversion with ease (almost complete port of RubyMoney)
• sass.cr - Compile SASS/SCSS to CSS (libsass binding)
• tssc.cr - Time::Span String Converter (incl. JSON & YAML support)

Cryptography

• cmac - Crystal implementation of Cipher-based Message Authentication Code (CMAC)
• ed25519 - the Ed25519 elliptic curve public-key signature system described in [RFC 8032]
• monocypher.cr - Crystal wrapper for the Monocypher crypto library
• sodium.cr - Crystal wrapper for the libsodium crypto API

Data Formats

• BinData - Binary data parser helper with an ASN.1 parser
• config.cr - Easy to use configuration format parser
• crinder - Class based json renderer
• Crystalizer - (De)serialize any Crystal object; supporting JSON, YAML, and Byte formats out of the box
• CSV - parsing and generating for comma-separated values (Crystal stdlib)
• front_matter.cr - Separates a files front matter from its content
• geoip2.cr - GeoIP2 reader
• HAR - HAR (HTTP Archive) parser
• INI - INI file parser (Crystal stdlib)
• jmespath.cr - Crystal implementation of JMESPath, a query language for JSON
• JSON - parsing and generating JSON documents (Crystal stdlib)
• json-schema - convert JSON serializable classes into a JSON Schema representation
• JSON::OnSteroids - handle and mutate JSON document easily
• maxminddb.cr - MaxMindDB reader
• toml.cr - TOML parser
• toon-crystal - TOON (Token-Oriented Object Notation) parser
• XML - parsing and generating XML documents (Crystal stdlib)
• YAML - parsing and generating YAML documents (Crystal stdlib)

Data Generators

• faker - A library for generating fake data
• hashids.cr - A library to generate YouTube-like ids from one or many numbers
• prime - A prime number generator

Database Drivers/Clients

• couchdb.cr - CouchDB client
• cryomongo - MongoDB driver
• crystal-db - Common db api
• crystal-ldap - LDAP client
• crystal-mysql - MySQL connector for Crystal
• crystal-pg - A Postgres driver
• crystal-redis - Full featured Redis client
• crystal-rethinkdb - Driver for RethinkDB / RebirthDB
• crystal-sqlite3 - SQLite3 bindings
• leveldb - Crystal bindings for LevelDB
• rocksdb.cr - RocksDB client
• surrealdb.cr - Unoffical SurrealDB HTTP & Websocket Client

Database Tools

• migrate - A simpler database migration tool with transactions

Debugging

• backtracer.cr - Shard aiming to assist with parsing backtraces into a structured form
• debug.cr - debug!(…) macro for pp-style debugging

Dependency Injection

• Athena Dependency Injection - Robust dependency injection service container framework
• Crystal-DI - Lightweight DI Container
• HardWire - A compile-time non-intrusive dependency injection system
• syringe - A simple and basic dependency injection shard for crystal

Email

• carbon - Fun, testable, and adapter-based email library
• crystal-email - Simple e-mail sending library
• CrystalEmail - A RFC compliant Email validator
• sendgrid.cr - Simple Sendgrid Client

Environment Management

• asdf-crystal - Plugin for asdf version manager
• crenv - Crystal version manager
• rcm.cr - Redis Cluster Manager
• vfox-crystal - Plugin for vfox version manager

Examples and funny stuff

• blackjack-cr - Console Blackjack
• crystal-patterns - Examples of GOF patters
• crystalworld - realworld.io back-end API implementation
• exercism-crystal - Exercism exercises
• try.cr - Try monad

Framework Components

• Athena Event Dispatcher - A Mediator and Observer pattern event library
• Athena Negotiation - Framework agnostic content negotiation library
• device_detector - Shard for detect device by user agent string
• Exception Page - An exceptional exception page for Crystal web libraries and frameworks
• graphql - Type-safe GraphQL server implementation
• graphql-crystal - GraphQL implementation
• kemal-identity - Authentication and identity primitives with first-class Kemal integration
• kemal-session - Session handler for Kemal
• mochi - Authentication shard inspired by Devise supporting: Authenticable, Confirmable, Invitable & more
• motion.cr - Object oriented frontend library for Amber
• multi-auth - Standardized multi-provider OAuth2 authentication (inspired by omniauth)
• praetorian - Minimalist authorization library inspired by Pundit
• rbacr - Role-Based Access Control system with a clean, type-safe DSL for roles, privileges, and authorization logic
• Shield - Comprehensive security for Lucky framework
• shrine.cr - File Attachment toolkit for Crystal applications. Heavily inspired by Shrine for Ruby
• tourmaline - Telegram bot framework with an API loosely based on telegraf.js

Game Development

• CrSFML - Bindings to SFML multimedia/game library
• crystal-chipmunk - Bindings to Chipmunk, a fast and lightweight 2D game physics library
• crystal-imgui-sfml - Bindings to integrate Dear ImGui into an SFML project
• entitas.cr - A Entity Component System Framework for Crystal
• MyECS - A Sparse Entity Component System Framework for Crystal
• Raylib-cr - Direct bindings to Raylib, which supports Linux, Windows, and Mac
• SDL-Crystal-Bindings - Direct (unsafe) bindings to SDL2, intended for writing own game libraries

GUI Development

• CrymbleUI - A nice and fast GUI framework for Crystal. Declarative DSL, Reactive State, Performant, Rich Widget Set including VirtualMatrix and RecursiveGrid
• crystal-imgui - Bindings to Dear ImGui, an immediate-mode graphical UI library
• GTK4.cr - Bindings for GTK4 with Crystalized API
• Iu - UI framework based on the Fusion/libui.cr library, with custom elements and modified bindings from hedron-crystal/hedron
• Ultimate GTK4 Crystal Guide - Learn how to create premium GTK4 apps in Crystal

HTML Builders

• blueprint - Write reusable and testable HTML templates in plain Crystal
• form_builder.cr - Dead simple HTML form builder for Crystal with built-in support for many popular UI libraries such as Bootstrap
• to_html - The fastest HTML builder engine for Crystal
• Water - A library for writing HTML in plain Crystal

HTML/XML Parsing

• docx_cr_converter - parse DOCX Word
• lexbor - Fast HTML5 Parser that includes CSS selectors

HTTP

• Cable - An ActionCable “port” to Crystal, framework agnostic, 100% compatible with the ActionCable JS Client
• cossack - Simple flexible HTTP client
• crest - Simple HTTP and REST client, inspired by the Ruby’s RestClient gem
• crul - Command line HTTP client
• cryload - cryload is a powerful, fast, and practical HTTP benchmarking tool for stress testing APIs and web services
• digest-auth - Digest authentication
• halite - Crystal HTTP Requests with a chainable REST API, built-in sessions and loggers
• http-multiserver.cr - Mounting multiple servers via routes (a.k.a. URL mapping)
• http-params-serializable - HTTP params (de)serialization, applicable to URL queries and URL-encoded forms
• http-protection - Protection against typical web attacks
• http2 - HTTP/2 Protocol Implementation
• HTTP::Client - HTTP client (Crystal stdlib)
• HTTP::Server - HTTP server (Crystal stdlib)
• HTTP::WebSocket - HTTP WebSocket client (Crystal stdlib)
• link-header - HTTP Link Header Parser
• ntlm - NTLM authentication
• proxy-fetcher.cr - Proxy lists fetching & validating library
• sse.cr - Server-Sent Events client

Image processing

• celestine - Create SVG images using a DSL
• ffmpeg - FFmpeg bindings that works with StumpyPNG to extract frames
• Pluto - A fast and convenient image processing library
• stumpy_png - Read and write PNG images

Implementations/Compilers

• charly - Charly Programming Language
• cltk - A crystal port of the Ruby Language Toolkit
• crisp - Lisp dialect implemented with Crystal
• GiavaScript - Open-source, cross-platform JavaScript runtime
• LinCAS-lang - A programming language for scientific computation
• mint-lang - A refreshing programming language for the front-end web
• myst-lang - A practical, dynamic language designed to be written and understood as easily and efficiently as possible
• novika - A free-form, moldable, interpreted programming language
• runic-lang - In-design toy language

Internationalization

• crystal-i18n - An internationalization library inspired by Ruby-I18n
• i18n.cr - Internationalization shard
• Lens - A multiformat internationalization (i18n) shard for Crystal. Supports Gettext, Ruby YAML, etc.
• Rosetta - A blazing fast internationalization (i18n) library with compile-time key lookup supporting YAML and JSON formats

Logging and monitoring

• crafana - A Grafana library to help autogenerate dashboards
• fiber_metrics.cr - Track run time, wait time, or memory allocations per Fiber, method or block
• Log - logging utility (Crystal stdlib)
• statsd.cr - Statsd client library

Machine Learning

• ai4cr - Artificial Intelligence (based on https://github.com/SergioFierens/ai4r)
• Cadmium - NLP library based heavily on natural
• crystal-fann - FANN (Fast Artifical Neural Network) binding
• mxnet.cr - Bindings for MXNet
• shainet - SHAInet (Neural Network in pure crystal)

Markdown/Text Processors

• cr-cmark-gfm - Crystal C bindings for cmark-gfm to work with Commonmark and Github Flavored Markdown
• markd - Yet another markdown parser built for speed, Compliant to CommonMark specification

Misc

• aasm.cr - Easy to use finite state machine for Crystal classes
• any_hash.cr - Recursive Hash with better JSON::Any included
• anyolite - Full mruby interpreter with simple bindings, allowing for easy scripting support in projects
• burocracia.cr - burocracia.cr the dependecyless shard to validate, generate and format Brazilian burocracias such as CPF, CNPJ and CEP
• callbacks - Expressive callbacks module
• circuit_breaker - Implementation of the circuit breaker pattern
• cpf_cnpj - Provide utilities for validating and formatting CPF and CNPJ identifiers
• CrSignals - Signals/slots notification library
• crystal-binary_parser - Binary parser
• crystal-web-framework-stars - Web frameworks for Crystal, most starred on Github
• crz - Functional programming library
• defined - macros for conditional compilation based on constant definitions, version requirements, or environment variable settings
• emoji.cr - Emoji library
• gphoto2-web.cr - Web API for libgphoto2
• immutable - Implementation of thread-safe, persistent, immutable collections
• iterm2 - Display images within the terminal using the ITerm2 Inline Images Protocol
• lua.cr - Bindings to liblua and a wrapper around it
• luajit.cr - LuaJIT bindings for Crystal
• monads - Monad implementation
• observable - Implementation of the observer pattern
• pinger - Ping IP addresses and DNS entries without requiring sudo
• port_midi - Crystal C bindings for the PortMIDI cross-platform MIDI I/O library
• retriable.cr - Simple DSL to retry failed code blocks
• sentry - Build/Runs your crystal application, watches files, and rebuilds/restarts app on file changes.
• serf-handler.cr - Framework for building Serf handlers, with a suite of useful builtin capabilities
• simple_retry - Simple tool for retrying failed code blocks
• sslscan.cr - Crystal shard wrapping the rbsec/sslscan utility
• version_tools - Version-dependent behaviour, specified at compile-time
• wafalyzer - Web Application Firewall (WAF) Detector - shard + cli
• zaru_crystal - Filename sanitization

Network Protocols

• amqp-client.cr - AMQP 0-9.1, a messaging protocol, implemented by eg. RabbitMQ
• connect-proxy - Connect method style of HTTP tunnelling / HTTP proxy
• cr-xmpp - XMPP/Jabber Library
• Crirc - IRC protocol implementation (Client, Server, Bots)
• crystal-bacnet - BACnet protocol implementation with BACnet/IP client
• crystal-json-socket - JSON-socket client & server implementation. Inspired by and compatible with node-json-socket and ruby-json-socket
• crystal-mqtt - A MQTT client
• crystal-snmp - An SNMP implementation with version 1, 2c and 3 support
• crystal-swim - Decentralized cluster discovery and eventually consistent failure detection using SWIM
• dns - DNS protocol implementation and resolver
• fast_irc.cr - Fast IRC parser/generator
• jwt - Implementation of JWT (JSON Web Token)
• knx - KNX protocol implementation supporting multicast, unicast and TCP/IP tunnelling
• Matter - Matter protocol for smart home and Internet of things (IoT) devices
• mDNS - DNS Service Discovery and multicast DNS
• mqtt-client.cr - A fast and lightweight MQTT client
• msgpack-crystal - MessagePack library
• OAuth - OAuth consumer (Crystal stdlib)
• OAuth2 - OAuth2 client (Crystal stdlib)
• OpenSSL - bindings to libssl (Crystal stdlib)
• simple_rpc - RPC Server and Client for Crystal. Implements msgpack-rpc protocol
• stomp - STOMP protocol
• telnet.cr - Telnet protocol
• transfer_more - Clone of transfer.sh to uploads files

Networking

• ipaddress.cr - Library to handle IPv4 and IPv6 addresses
• mac-address - Library for working with MAC addresses

ORM/ODM Extensions

• avram - A database wrapper for reading, writing, and migrating Postgres databases
• clear - ORM specialized to PostgreSQL only but with advanced features
• crecto - Database wrapper, based on Ecto
• granite - ORM for Postgres, Mysql, Sqlite
• jennifer.cr - Active Record pattern implementation with flexible query chainable builder and migration system
• lustra - Advanced PostgreSQL ORM with ActiveRecord pattern, full-text search, geometry types, and more
• rethinkdb-orm - ORM for RethinkDB / RebirthDB

Package Management

• shards - Dependency manager for the Crystal

Processes and Threads

• await_async - Add keywords await & async in Crystal Lang
• concurrent.cr - Simplified concurrency using streams/pipelines, waitgroups, semaphores, smores and more
• neph - A modern command line job processor that can execute jobs concurrently
• promise - A Promise implementation with type inference
• werk - Dead simple task runner with concurrent support, ideal for local CI

Project Generators

• crygen - A library that allows to generate the Crystal code
• crystal_lib - Automatic binding generator for native libraries
• fez - A Kemal application generator
• libgen - Automatic bindings generator configured using JSON/YAML files

Queues and Messaging

• crafka - Apache Kafka library utilizing librdkafka
• mosquito - Redis backed periodic and ad hoc job processing
• NATS.io - NATS client
• sidekiq.cr - Simple, efficient job processing

Routing

• orion - A minimal, rails-esque routing library
• router.cr - Minimum but powerful http router for HTTP::Server

Scheduling

• cronaute - Cron daemon for containers, shipped as a single static binary with a read-only dashboard
• crystime - Advanced time, calendar, schedule, and remind library
• schedule.cr - Run periodic tasks
• tasker - A high precision scheduler including timezone aware cron jobs

Science and Data analysis

• alea - Repeatable sampling, CDF and other utilities to work with probability distributions
• ishi - Graph plotting package with a small API and sensible defaults powered by gnuplot
• linalg - Linear algebra library inspired by MATLAB and SciPy.linalg
• num.cr - Numerical computing library supporting N-Dimensional data
• predict.cr - Satellite prediction library using the sgp4 model
• quartz - Modeling and simulation framework

Search

• hermes - Data Mapper pattern implementation for ElastiSearch

Security

• cyclonedx-cr - CycloneDX SBOM(Software Bill of Materials) generator for Crystal projects
• OWASP Noir - Attack surface detector that identifies endpoints by static analysis
• XSSMaze - XSSMaze is a web service that tests security tools using diverse XSS cases

Serverless Computing

• crystal_openfaas - Template to enable crystal as first class citizens in OpenFaaS
• secrets-env - Extends ENV module to read values injected by docker / kubernetes secrets and other orchestration tools

System

• baked_file_system - Virtual file system implementation
• hardware - Get CPU, Memory and Network informations of the running OS and its processes

Task management

• cake - Production-ready Make-like utility tool
• sam - Another one Rake-like task manager with namespacing and arguments system

Template Engine

• crinja - An implementation of the Jinja2 template engine
• crustache - {{Mustache}} for Crystal
• ECR (Embedded Crystal) - compile time template language which uses plain crystal expressions (Crystal stdlib)
• Jbuilder - Generate JSON objects with a Builder-style DSL, inspired by jbuilder
• Kilt - Abstraction layer for template engines
• Slang - Lightweight, terse, templating language inspired by Ruby’s Slim
• teeplate - A library for rendering multiple template files

Testing

• Athena Spec - Common/helpful Spec compliant testing utilities
• crotest - A tiny and simple test framework
• crytic - Mutation testing framework
• hashr - A tiny class makes test on JSON response easier
• LuckyFlow - Automated browser tests similar to Capybara
• mass-spec - Web API testing library
• microtest - Small opinionated testing library focusing on power asserts
• minitest.cr - Library for unit tests and assertions
• mocks.cr - Mocking library for Crystal
• selenium.cr - Selenium client for interacting with web pages for browser automation
• Spec - spec framework (Crystal stdlib)
• spectator - Feature rich spec framework that uses the modern expect syntax
• timecop.cr - Library for mocking with Time.now. Inspired by the timecop ruby gem
• vcr - A HTTP capture and replay implementation for crystal
• webdriver_pump - Page Object library. Inspired by Ruby’s WatirPump
• webmock.cr - Library for stubbing HTTP::Client requests

Third-party APIs

• amazonite - An unofficial SDK supporting popular AWS APIs
• aws-signer.cr - This library signs your HTTP requests using AWS v4
• awscr-s3 - AWS S3 interface
• awscr-signer - Sign HTTP::Request objects and generate presigned post forms
• crystal-consul - Consul API client
• crystal-darksky - Wrapper for the Dark Sky API
• crystal-swapi - Star Wars API (SWAPI) wrapper
• crystal_slack - A tool that parses Slack slash commands or send incoming web hooks
• GDAX - GDAX REST and WebSocket API Wrapper with request signing
• gitlab.cr - GitLab API wrapper
• google - Google API wrapper
• host_meta - A Web Host Metadata (https://tools.ietf.org/html/rfc6415) client
• kube-client.cr - Kubernetes API Client
• mixpanel-crystal - A library for sending events to Mixpanel
• mollie.cr - Mollie Payments API wrapper (Creditcard, PayPal, Apple Pay, Sofort, Klarna, …)
• office365 - Microsoft Graph API wrapper
• pinboard.cr - Pinboard API
• raven.cr - Raven is a client for Sentry
• stripe.cr - Stripe api wrapper
• tmdb.cr - The Movie DB (TMDb) api wrapper
• twitter-crystal - A library to access the Twitter API
• web_finger - A WebFinger (https://tools.ietf.org/html/rfc7033) client
• ynab.cr - A library to interact with your YNAB data

TUI

• termisu - Minimalistic API for writing text-based user interfaces

Validation

• accord - Shareable validation library for Crystal Objects
• Athena Validator - Robust & flexible validation framework
• validations - Validations mixin
• validator - Data check and validation

Web Frameworks

• amber - Open source efficient and cohesive web application framework
• Athena - A web framework comprised of reusable, independent components
• grip - The microframework for writing powerful web applications
• kemal - Lightning Fast, Super Simple web framework. Inspired by Sinatra
• lucky - Catch bugs early, forget about most performance issues, and spend more time on code instead of debugging and writing tests
• marten - A web framework that makes building web applications easy, productive, and fun
• runcobo - An api framework with simple, intuitive and consistent DSL, using jbuilder to render json
• Shivneri - Component based MVC web framework for crystal targeting good code structures, modularity & performance
• spider-gazelle - A Rails esque web framework with a focus on speed and extensibility

Community

• Crystal Forum
• Crystal newsletter
• Gitter
• IRC - #crystal-lang on Libera
• Reddit
• Stackoverflow

Unofficial

• Crystal Programming Discord Server - Unofficial Discord server dedicated to the Crystal Programming Language
• Portuguese-speaking Telegram Group - Bem vindos ao Crystal Brasil!
• Russian-speaking Telegram Group - Добро пожаловать, товарищ!

Resources

• Crystal for Rubyists - Free book to bootstrap your Crystal journey
• Crystal Shards for Ruby Gems - A list of Ruby Gems and their Crystal Shards equivalents
• crystal-koans - Learn Crystal by writing unit tests
• crystal-lang.org - Official language site
• devdocs.io - API Documentation Browser with Crystal support
• Learn X in Y minutes - Quick tutorial on Crystal
• Programming Crystal - PragProg book to start your Crystal journey
• Usability of Programming Languages - Comparison of Python, Rust, Crystal

Official Documentation Translations

• br.crystal-lang.org - Brazilian
• ja.crystal-lang.org - Japanese
• kr.crystal-lang.org - Korean
• ru.crystal-lang.org - Russian
• tw.crystal-lang.org - Chinese Traditional

Services and Apps

• carc.in - A web service that runs your code and displays the result
• Crank - A Procfile-based application manager (like Foreman)
• cry - Ability to execute crystal code in a fashion similar to Ruby’s pry edit
• DeBot - IRC bot written in Crystal
• icr - Interactive console for Crystal (like IRB for Ruby)
• Invidious - Invidious is an alternative front-end to YouTube
• mpngin - A URL shortener with simple stats
• procodile - Run processes in the background (and foreground) on Mac & Linux from a Procfile (for production and/or development environments)
• quicktype - Generate models and serializers from JSON, JSON Schema, GraphQL, and TypeScript
• shards.info - Web service that lists all repositories on GitHub that have Crystal code in them. The sources are available on GitHub

Tools

• ast_helper - Helper tool to debug parser and formatter
• crystal-base - CentOS base docker image for Crystal development
• crystal-dash-docset - Dash docset generator
• port_ruby_to_crystal - A regex replace ruby script for port ruby code to crystal easier, reduce friction
• public_suffix - A small library designed to make the Public Suffix List (https://publicsuffix.org/) easier to use

DevOps

• ansible-crystal - Ansible playbook for installing crystal
• DPPM - An easy, universal way to install and manage applications as packages (mostly Linux)
• krikri - Fast Ansible-compatible automation engine

Editor Plugins

• Acme:
  • acmecrystal - Reformats crystal code in acme
• Atom
  • crystal-tools - Enables built in tools in Crystal compiler
  • language-crystal-actual - Crystal language support in Atom
• Emacs
  • crystal-mode - Crystal language support for Emacs (crystal-lang-tools/emacs-crystal-mode)
• Geany
  • geany-crystal - Crystal support for the Geany editor
• IntelliJ IDEA
  • intellij-crystal-lang - Crystal support for the JetBrains IDEs
• Lite-XL
  • lite-plugin-crystal - Crystal support for the Lite-XL editor
• Spacemacs
  • crystal-spacemacs-layer - Spacemacs contribution layer for Crystal
• Sublime
  • sublime-crystal - Crystal syntax highlighting for sublime Text
• TextMate
  • Crystal.tmbundle - Crystal syntax highlighting, compile, format command, snippets
• Vim
  • vim-crystal - Vim filetype support for Crystal
  • vim-slang - Vim filetype support for Slang Templating Engine
• Visual Studio Code
  • vscode-crystal-lang - Formatter, linter and syntax highlighting for cr and ecr files

LSP Language Server Protocol Implementations

• ameba-ls - Language Server for the Ameba linter
• crystalline - Crystalline is an implementation of the Language Server Protocol written in and for the Crystal Language
• scry - Code analysis server for Crystal implementing the Language Server Protocol

Shell plugins

• crun - Crystal Run : shebang wrapper for Crystal
• crystal-zsh - .oh-my-zsh plugin