For developers, who are building real-time data-driven applications, Redis is the preferred, fastest, and most feature-rich cache, data structure server, and document and vector query engine.

GoAccess is a real-time web log analyzer and interactive viewer that runs in a terminal in *nix systems or through your browser.

H2O - the optimized HTTP/1, HTTP/2, HTTP/3 server

Lightweight Ruby

A fast and lightweight IDE

The Rubinius Language Platform

Open source smart card tools and middleware. PKCS#11/MiniDriver

ruby bindings to libgit2

The Polipo caching HTTP proxy

The Rhodes framework is a platform for building locally executing, device-optimized mobile applications for all major smartphone devices.

PWM on the Raspberry pi - done properly (in hardware, stable)

a library for making a simple Wayland compositor

Simple evented I/O for Ruby.

(Very) basic UNIX-like operating system built when I was younger

darknet neural network addon for openFrameworks

Ruby binding for curses, ncurses, and PDCurses. Formerly part of the ruby standard library.

Ruby gem of the Arduino wiring-like C library WiringPi

nRF24L01+ Library for MSP430 microcontroller line

Version 2.x of Gordon Henderson's Arduino-like WiringPi GPIO functions, wrapped up for Ruby.

Ruby bindings for the GTK+ port of WebKit.

image manipulation tool for ruby and gosu

OpenCT implements drivers for several smart card readers

Efficient Voronoi diagrams and Delaunay trianglation for Ruby

Ruby wrapper around djb's NaCl networking and cryptography library