Crystal

Inserting values into a sorted array

BlurHash implementation

Compile-time Trie

HOTP and TOTP implementation for two factor authentication

Implementation of Linked List

A pure Vector Math library

A Generic Algorithm Library

A collection of containers and algorithms

A Chronologically Sortable UUID

Collection of edit distance algorithms

A Crystal port of awesome Fzy project fuzzy finder algorithm

A fast and efficient QR Code implementation

Collection of graph datastructure and algorithms

An Implementation of the Haversine formula

HMAC-based Extract-and-Expand Key Derivation Function rfc5869

An implementation of "K-Dimensional Tree" and "N-Nearest Neighbors"

K-Sortable Globally Unique IDs

Build Markov Chains and run Markov Processes

Implementation of a multiset

Naming Things with Hashes rfc6920

QR Code generator

Radix Tree implementation

S2 Geometry for spatial indexing

SRP-6a protocol for authentication over an insecure network

Password Authenticated Key Exchange (PAKE) protocol, comparable to SRP-6a

Splay Tree implementation that conforms to the Hash ducktype

Implementation of the Verhoeff checksum algorithm

A custom blockchain platform

A minimal blockchain testbed

Elliptic curve used in the public-private-key cryptography

Bindings for Augeas

Libclang bindings

Bindings for libncursesw and crt

Bindings for GNU Scientific Library

Bindings for Hunspell

Bindings for the Duktape javascript engine

Bindings for FFTW library

Bindings for the libgphoto2 library

Bindings for the gpiod library (general purpose IO control and feedback)

Bindings for the ICU library

Bindings for Libnotify

Bindings for NLOpt

Bindings for libpcap

Bindings for OpenBSD's pledge(2)

Bindings for libssh2 library

Bindings for syslog

Bindings for Video4Linux2

Bindings for the wasmer WebAssembly runtime

Bindings for Win32 API

Bindings for libxdo (xdotool)

Implementation of a memcached client

A robust DSL for writing command line interfaces

Allows for the creation of CLI based commands

A simple declarative command line interface builder

Slim command line interface builder

A modular, non-macro-based command line interface library

Command-line interface builder

A lightweight text user interface library in Crystal

command-line options processing (Crystal stdlib)

A highly flexible Crystal CLI builder in the style of OptionParser

Tiny tool to make your CLI output 🌈 coloured

Command-line application that performs currency conversion via the Fixer API

A light CLI text editor/IDE

A git cli wrapper querying and cloning remote repositories with minimal data transfer

A CLI tool to quickly create and manage Kubernetes clusters in Hetzner Cloud

Simple and straightforward large files finder utility in command line

Start a jitsi meeting quickly from the comfort of your command line

A performant, and portable jq wrapper to facilitate the consumption and output of formats other than JSON; using jq filters to transform the data

A simple and customizable progress bar

A flexible terminal table generator

Generate ASCII character tables with support for spanning cells over multiple columns

A static code analysis tool

A tool that provides an UML class diagram generator for any Crystal projects

Using multiple ways to find programming language used in files, based on Github's Linguist

Readers and writers of Tar archive format

readers and writers of gzip format (Crystal stdlib)

compression of series of coordinates

Snappy compression format reader/writer for Crystal

readers and writers of zip format (Crystal stdlib)

readers and writers of zlib format (Crystal stdlib)

Bindings for Zstandard compression library

Loads .env file

Load environment variables from YAML

A simple YAML to ENV config loader

Type safe configuration for your classes and modules

Load and parse a configuration in JSON, YAML, dotenv formats

Base62 encoder/decoder, well suited for url-shortening

Tool for converting units of measure (miles to kilometers, celsius to fahrenheit etc)

Handling money and currency conversion with ease (almost complete port of RubyMoney)

Compile SASS/SCSS to CSS (libsass binding)

Time::Span String Converter (incl. JSON & YAML support)

Crystal implementation of Cipher-based Message Authentication Code (CMAC)

the Ed25519 elliptic curve public-key signature system described in [RFC 8032]

Crystal wrapper for the Monocypher crypto library

Crystal wrapper for the libsodium crypto API

Binary data parser helper with an ASN.1 parser

Easy to use configuration format parser

Class based json renderer

(De)serialize any Crystal object; supporting JSON, YAML, and Byte formats out of the box

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

Separates a files front matter from its content

GeoIP2 reader

HAR (HTTP Archive) parser

INI file parser (Crystal stdlib)

Crystal implementation of JMESPath, a query language for JSON

parsing and generating JSON documents (Crystal stdlib)

convert JSON serializable classes into a JSON Schema representation

handle and mutate JSON document easily

MaxMindDB reader

TOML parser

TOON (Token-Oriented Object Notation) parser

parsing and generating XML documents (Crystal stdlib)

parsing and generating YAML documents (Crystal stdlib)

A library for generating fake data

A library to generate YouTube-like ids from one or many numbers

A prime number generator

CouchDB client

MongoDB driver

Common db api

LDAP client

MySQL connector for Crystal

A Postgres driver

Full featured Redis client

Driver for RethinkDB / RebirthDB

SQLite3 bindings

Crystal bindings for LevelDB

RocksDB client

Unoffical SurrealDB HTTP & Websocket Client

A simpler database migration tool with transactions

Shard aiming to assist with parsing backtraces into a structured form

debug!(…) macro for pp-style debugging

Robust dependency injection service container framework

Lightweight DI Container

A compile-time non-intrusive dependency injection system

A simple and basic dependency injection shard for crystal

Fun, testable, and adapter-based email library

Simple e-mail sending library

A RFC compliant Email validator

Simple Sendgrid Client

Plugin for asdf version manager

Crystal version manager

Redis Cluster Manager

Plugin for vfox version manager

Console Blackjack

Examples of GOF patters

realworld.io back-end API implementation

Exercism exercises

Try monad

A Mediator and Observer pattern event library

Framework agnostic content negotiation library

Shard for detect device by user agent string

An exceptional exception page for Crystal web libraries and frameworks

Type-safe GraphQL server implementation

GraphQL implementation

Session handler for Kemal

Authentication shard inspired by Devise supporting: Authenticable, Confirmable, Invitable & more

Object oriented frontend library for Amber

Standardized multi-provider OAuth2 authentication (inspired by omniauth)

Minimalist authorization library inspired by Pundit

Comprehensive security for Lucky framework

File Attachment toolkit for Crystal applications. Heavily inspired by Shrine for Ruby

Telegram bot framework with an API loosely based on telegraf.js

Bindings to SFML multimedia/game library

Bindings to Chipmunk, a fast and lightweight 2D game physics library

Bindings to integrate Dear ImGui into an SFML project

A Entity Component System Framework for Crystal

A Sparse Entity Component System Framework for Crystal

Direct bindings to Raylib, which supports Linux, Windows, and Mac

Direct (unsafe) bindings to SDL2, intended for writing own game libraries

Bindings to Dear ImGui, an immediate-mode graphical UI library

Bindings for GTK4 with Crystalized API

UI framework based on the Fusion/libui.cr library, with custom elements and modified bindings from hedron-crystal/hedron

Learn how to create premium GTK4 apps in Crystal

Write reusable and testable HTML templates in plain Crystal

Dead simple HTML form builder for Crystal with built-in support for many popular UI libraries such as Bootstrap

The fastest HTML builder engine for Crystal

A library for writing HTML in plain Crystal

parse DOCX Word

Fast HTML5 Parser that includes CSS selectors

An ActionCable "port" to Crystal, framework agnostic, 100% compatible with the ActionCable JS Client

Simple flexible HTTP client

Simple HTTP and REST client, inspired by the Ruby's RestClient gem

Command line HTTP client

Digest authentication

Crystal HTTP Requests with a chainable REST API, built-in sessions and loggers

Mounting multiple servers via routes (a.k.a. URL mapping)

HTTP params (de)serialization, applicable to URL queries and URL-encoded forms

Protection against typical web attacks

HTTP/2 Protocol Implementation

HTTP client (Crystal stdlib)

HTTP server (Crystal stdlib)

HTTP WebSocket client (Crystal stdlib)

HTTP Link Header Parser

NTLM authentication

Proxy lists fetching & validating library

Server-Sent Events client

Create SVG images using a DSL

FFmpeg bindings that works with StumpyPNG to extract frames

A fast and convenient image processing library

Read and write PNG images

Charly Programming Language

A crystal port of the Ruby Language Toolkit

Lisp dialect implemented with Crystal

A programming language for scientific computation

A refreshing programming language for the front-end web

A practical, dynamic language designed to be written and understood as easily and efficiently as possible

A free-form, moldable, interpreted programming language

In-design toy language

An internationalization library inspired by Ruby-I18n

Internationalization shard

A multiformat internationalization (i18n) shard for Crystal. Supports Gettext, Ruby YAML, etc.

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

A Grafana library to help autogenerate dashboards

Track run time, wait time, or memory allocations per Fiber, method or block

logging utility (Crystal stdlib)

Statsd client library

Artificial Intelligence (based on https://github.com/SergioFierens/ai4r)

NLP library based heavily on natural

FANN (Fast Artifical Neural Network) binding

Bindings for MXNet

SHAInet (Neural Network in pure crystal)

Crystal C bindings for cmark-gfm to work with Commonmark and Github Flavored Markdown

Yet another markdown parser built for speed, Compliant to CommonMark specification

Easy to use finite state machine for Crystal classes

Recursive Hash with better JSON::Any included

Full mruby interpreter with simple bindings, allowing for easy scripting support in projects

burocracia.cr the dependecyless shard to validate, generate and format Brazilian burocracias such as CPF, CNPJ and CEP

Expressive callbacks module

Implementation of the circuit breaker pattern

Provide utilities for validating and formatting CPF and CNPJ identifiers

Signals/slots notification library

Binary parser

Web frameworks for Crystal, most starred on Github

Functional programming library

macros for conditional compilation based on constant definitions, version requirements, or environment variable settings

Emoji library

Web API for libgphoto2

Implementation of thread-safe, persistent, immutable collections

Display images within the terminal using the ITerm2 Inline Images Protocol

Monad implementation

Implementation of the observer pattern

Ping IP addresses and DNS entries without requiring sudo

Crystal C bindings for the PortMIDI cross-platform MIDI I/O library

Simple DSL to retry failed code blocks

Build/Runs your crystal application, watches files, and rebuilds/restarts app on file changes.

Framework for building Serf handlers, with a suite of useful builtin capabilities

Simple tool for retrying failed code blocks

Crystal shard wrapping the rbsec/sslscan utility

Version-dependent behaviour, specified at compile-time

Web Application Firewall (WAF) Detector - shard + cli

Filename sanitization

AMQP 0-9.1, a messaging protocol, implemented by eg. RabbitMQ

Connect method style of HTTP tunnelling / HTTP proxy

XMPP/Jabber Library

IRC protocol implementation (Client, Server, Bots)

BACnet protocol implementation with BACnet/IP client

JSON-socket client & server implementation. Inspired by and compatible with node-json-socket and ruby-json-socket

A MQTT client

An SNMP implementation with version 1, 2c and 3 support

DNS protocol implementation and resolver

Fast IRC parser/generator

Implementation of JWT (JSON Web Token)

KNX protocol implementation supporting multicast, unicast and TCP/IP tunnelling

DNS Service Discovery and multicast DNS

A fast and lightweight MQTT client

MessagePack library

OAuth consumer (Crystal stdlib)

OAuth2 client (Crystal stdlib)

bindings to libssl (Crystal stdlib)

RPC Server and Client for Crystal. Implements msgpack-rpc protocol

STOMP protocol

Telnet protocol

Clone of transfer.sh to uploads files

Library to handle IPv4 and IPv6 addresses

Library for working with MAC addresses

A database wrapper for reading, writing, and migrating Postgres databases

ORM specialized to PostgreSQL only but with advanced features

Database wrapper, based on Ecto

ORM for Postgres, Mysql, Sqlite

Active Record pattern implementation with flexible query chainable builder and migration system

ORM for RethinkDB / RebirthDB

Dependency manager for the Crystal

Add keywords await & async in Crystal Lang

Simplified concurrency using streams/pipelines, waitgroups, semaphores, smores and more

A modern command line job processor that can execute jobs concurrently

A Promise implementation with type inference

Dead simple task runner with concurrent support, ideal for local CI

A library that allows to generate the Crystal code

Automatic binding generator for native libraries

A Kemal application generator

Automatic bindings generator configured using JSON/YAML files

Apache Kafka library utilizing librdkafka

Redis backed periodic and ad hoc job processing

NATS client

Simple, efficient job processing

A minimal, rails-esque routing library

Minimum but powerful http router for HTTP::Server

Advanced time, calendar, schedule, and remind library

Run periodic tasks

A high precision scheduler including timezone aware cron jobs

Repeatable sampling, CDF and other utilities to work with probability distributions

Graph plotting package with a small API and sensible defaults powered by gnuplot

Linear algebra library inspired by MATLAB and SciPy.linalg

Numerical computing library supporting N-Dimensional data

Satellite prediction library using the sgp4 model

Modeling and simulation framework

Data Mapper pattern implementation for ElastiSearch

CycloneDX SBOM(Software Bill of Materials) generator for Crystal projects

Attack surface detector that identifies endpoints by static analysis

XSSMaze is a web service that tests security tools using diverse XSS cases

Template to enable crystal as first class citizens in OpenFaaS

Extends ENV module to read values injected by docker / kubernetes secrets and other orchestration tools

Virtual file system implementation

Get CPU, Memory and Network informations of the running OS and its processes

Production-ready Make-like utility tool

Another one Rake-like task manager with namespacing and arguments system

An implementation of the Jinja2 template engine

{{Mustache}} for Crystal

compile time template language which uses plain crystal expressions (Crystal stdlib)

Generate JSON objects with a Builder-style DSL, inspired by jbuilder

Abstraction layer for template engines

Lightweight, terse, templating language inspired by Ruby's Slim

A library for rendering multiple template files

Common/helpful Spec compliant testing utilities

A tiny and simple test framework

Mutation testing framework

A tiny class makes test on JSON response easier

Automated browser tests similar to Capybara

Web API testing library

Small opinionated testing library focusing on power asserts

Library for unit tests and assertions

Mocking library for Crystal

Selenium client for interacting with web pages for browser automation

spec framework (Crystal stdlib)

Feature rich spec framework that uses the modern expect syntax

Library for mocking with Time.now. Inspired by the timecop ruby gem

A HTTP capture and replay implementation for crystal

Page Object library. Inspired by Ruby's WatirPump

Library for stubbing HTTP::Client requests

An unofficial SDK supporting popular AWS APIs

This library signs your HTTP requests using AWS v4

AWS S3 interface

Sign HTTP::Request objects and generate presigned post forms

Consul API client

Wrapper for the Dark Sky API

Star Wars API (SWAPI) wrapper

A tool that parses Slack slash commands or send incoming web hooks

GDAX REST and WebSocket API Wrapper with request signing

GitLab API wrapper

Google API wrapper

A Web Host Metadata (https://tools.ietf.org/html/rfc6415) client

Kubernetes API Client

A library for sending events to Mixpanel

Mollie Payments API wrapper (Creditcard, PayPal, Apple Pay, Sofort, Klarna, ...)

Microsoft Graph API wrapper

Pinboard API

Raven is a client for Sentry

Stripe api wrapper

The Movie DB (TMDb) api wrapper

A library to access the Twitter API

A WebFinger (https://tools.ietf.org/html/rfc7033) client

A library to interact with your YNAB data

Shareable validation library for Crystal Objects

Robust & flexible validation framework

Validations mixin

Data check and validation

Open source efficient and cohesive web application framework

A web framework comprised of reusable, independent components

The microframework for writing powerful web applications

Lightning Fast, Super Simple web framework. Inspired by Sinatra

Catch bugs early, forget about most performance issues, and spend more time on code instead of debugging and writing tests

A web framework that makes building web applications easy, productive, and fun

An api framework with simple, intuitive and consistent DSL, using jbuilder to render json

Component based MVC web framework for crystal targeting good code structures, modularity & performance

A Rails esque web framework with a focus on speed and extensibility

#crystal-lang on Libera

Unofficial Discord server dedicated to the Crystal Programming Language

Bem vindos ao Crystal Brasil!

Добро пожаловать, товарищ!

Free book to bootstrap your Crystal journey

A list of Ruby Gems and their Crystal Shards equivalents

Learn Crystal by writing unit tests

Official language site

API Documentation Browser with Crystal support

Quick tutorial on Crystal

PragProg book to start your Crystal journey

Comparison of Python, Rust, Crystal

Brazilian

Japanese

Korean

Russian

Chinese Traditional

A web service that runs your code and displays the result

A Procfile-based application manager (like Foreman)

Ability to execute crystal code in a fashion similar to Ruby's pry edit

IRC bot written in Crystal

Interactive console for Crystal (like IRB for Ruby)

Invidious is an alternative front-end to YouTube

A URL shortener with simple stats

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

Generate models and serializers from JSON, JSON Schema, GraphQL, and TypeScript

Web service that lists all repositories on GitHub that have Crystal code in them. The sources are available on GitHub

Helper tool to debug parser and formatter

CentOS base docker image for Crystal development

Dash docset generator

A regex replace ruby script for port ruby code to crystal easier, reduce friction

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

Ansible playbook for installing crystal

An easy, universal way to install and manage applications as packages (mostly Linux)

Acme:acmecrystal - Reformats crystal code in acme

Crystalline is an implementation of the Language Server Protocol written in and for the Crystal Language

Code analysis server for Crystal implementing the Language Server Protocol

Crystal Run : shebang wrapper for Crystal

.oh-my-zsh plugin