- Bundler - Bundler maintains a consistent environment for ruby applications. It tracks an application's code and the rubygems it needs to run, so that an application will always have the exact gems (and versions) that it needs to run.
- rabl - General ruby templating with json, bson, xml, plist and msgpack support
- Thin - Very fast and lightweight Ruby web server
- SimpleCov - SimpleCov is a code coverage analysis tool for Ruby 1.9.
- Zeus - Zeus preloads your Rails app so that your normal development tasks such as console, server, generate, and specs/tests take less than one second.
- factory_girl - factory_girl is a fixtures replacement with a straightforward definition syntax, support for multiple build strategies (saved instances, unsaved instances, attribute hashes, and stubbed objects), and support for multiple factories for the same class (user, admin_user, and so on), including factory inheritance.
- Forward - Forward your localhost to a publicly-accessible url