Ruby on Rails is a full-stack web framework optimized for programmer happiness and sustainable productivity. It encourages beautiful code by favoring convention over configuration.

Sinatra is a DSL for quickly creating web applications in Ruby with minimal effort.

Hanami is a web framework for Ruby

Rack provides a minimal, modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call. Also see https://rack.github.io/.

The Godfather of Sinatra provides a full-stack agnostic framework on top of Sinatra

Routing tree web toolkit

Cuba is a microframework for web applications.

Cramp is a framework for developing asynchronous web applications.

Design-First Web Framework

The web app builder for Rails

Nothing to see yet.

Ramaze is a simple and modular web framework

A light-weight Sinatra-inspired web framework for web sites and applications of any size.

The Plezi.io Ruby Framework for real time web applications.

Rango is ultralightweight, ultracustomizable, ultracool web framework deeply inspired by Django.

Scalable Framework aimed at Speed and Simplicity

Marley is a framework for quickly building RESTful web services and applications. Development is fast for two reasons: Marley implements lots of sensible defaults, all of which can be overridden and most of which can be overridden easily. And Marley servers exchange only data and metadata with clients.

A bliki-type web content thing.

Harbor Framework

Gin is a small Ruby web framework, built on Rack, which borrows from Sinatra expressiveness, and targets larger applications.

Strelka is a framework for creating and deploying Mongrel2[http://mongrel2.org/] web applications in Ruby. It's named after a lesser known {Russian cosmonaut}[http://en.wikipedia.org/wiki/Strelka_(dog)#Belka_and_Strelka] who was one of the first canine space travelers to orbit the Earth and return alive. Her name means "little arrow".

minature rails for stay-at-home moms

The super-friendly web framework.

A concurrent realtime web framework for Ruby

Merb. Pocket rocket web framework.

A microframework built on Rack.