The Mocktopus is a Sinatra/thin-based Web API that lets you mock your app dependencies

Ruby client for Moneybookers Automated Payment Interface and Payment Gateway

Library for the Microsoft® Translator API

Host your bookmarks or maintain a link blog

Because everyone loves Nachos!

this gem allows the usage of the newegg.com api to ascertain product information.

Ruby client for Nordea FileTransfer Web Services

NPR (npr.org) is a news organization. This gem helps you pull NPR content with a nice Ruby DSL.

Simple gem to enable rack powered Ruby apps to authenticate internally via casport with ease

Ruby gem for the Octopart API

Rails engine for authenticating internal applications and private-access products

Use the Online Scout Manager API (https://www.onlinescoutmanager.co.uk) to retrieve and save data.

Smart fields for your forms, similar to Formtastic or SimpleForm

Connects to the payone gateway and passes the parameters

Provide data on elements in the periodic table.

Ruby library for querying and mapping data through generic interfaces

A ruby wrapper to the Stack Exchange (Stack Overflow and friends) API.

Ruby wrapper for the Pivotal Tracker V3 API

Wrapper for the Plancast API

Rails 3.1 drop-in blog engine for existing Rails applications