Provides object geocoding (by street or IP address), reverse geocoding (coordinates to street address), distance queries for ActiveRecord and Mongoid, result caching, and more. Designed for Rails but works with Sinatra and other Rack frameworks too.

Redirect is a simple Ruby redirect DSL build on Rack. It's like a simple Ruby mod_rewrite, so you can write and test your redirects in Ruby.

Complete, fast and testable actions for Rack

This gem allows easy and flexible embedding of Google services (currently only analytics tracking) in Rack apps, including Ruby on Rails

Easy config, Rails and Rack application's configuration made easy.

Checks for AWS IP ranges, including adding to Rack trusted proxy list.

Rack metal with a better interface

A rack middleware for collecting JavaScript code coverages.

Sessionography has only one function: to replace Sinatra's session methods with a basic hash that persists across requests. Bypassing Rack::Session removes nearly all the complexity of unit and integration testing with session data.

DSL for running rack servers as easily as you can in javasript.

For use with Rails and the RequestId gem, this sets the request id so it can be sent on to internal http services.

Obscenity is a profanity filter gem for Ruby, Rails (through ActiveModel), and Rack middleware.

Scrap is a Rack endpoint designed to expose various garbage and memory-related metrics about your app. Intended for tracking down memory leaks and bloat.

Blackbeard is a Redis backed metrics collection system with a Rack dashboard. It dreams of being a replacement for rollout and split, but is early in its development.

Simple Rack middleware to log the heroku request id and write it to the end of html requests. Both optionally, of course.

Simple, fast HTML minification for Rack applications

Listen to your app.

Rack middleware to 404 touch icon requests from iOS devices

rails_angular_seo allows you to make your single-page apps (Backbone, Angular, etc) built on Rails SEO-friendly. It works by injecting a small rack middleware that will render pages as plain html, when the requester is one of the most common crawlers/bots out there (Google, Yahoo Baidu and Bing)

A collection of easily plugable rack authentication middlewares