Codecademy has expanded its API curriculum with several further sets of lessons. It now covers 22 APIs and the SkyDrive API is billed as coming soon.

Last month Codecademy launched a new track to help beginners to write apps and build websites using some popular APIs including the YouTube and bitly APIs.

Now you'll find more lessons with a set on the Twitter API, which enable you to access Twitter data from users, Tweets and timelines, heading the list.

Although Codeacademy's lessons are for beginners you need some programming skills from the outset. You need to have acquired the skill of reading code and following instructions to modify and add to the code snippets you are presented with.

Once you feel comfortable with the Codeacedemy approach it all fits into place.

(click to enlarge)

Ruby is the language used for the interactive lessons on using the Twitter API and if you are new to Ruby you'll find everything you need on Codeacademy. It has a full Ruby track, authored by Eric Weinstein, and if you are new to using web APIs there's a set of 19 exercises, also from Eric Weinstein that covers the basics common to APIs in general such as requests, responses, data formats, status codes, and more. Before embarking on the five exercises specific to the Twitter API you are expected to have completed the "How to Use APIs" set in Ruby.

The How to Use APIs are also available in Python and JavaScript, both of which are languages that you can learn from scratch on Codeacademy.

The other additions to the API curriculum, and their languages,  are:

• Box (Ruby) – Store and share content in the cloud using Box
  
  
• Evernote (Ruby) – Accessing and initializing an Evernote client, creating a note object, etc
  
  
• OAuth2 / GitHub (Ruby) – Guide to the OAuth2 protocol using GitHub
  
  
• Ordr.in (Ruby) – Create a food ordering application using Ordr.in
  
  
• Dwolla (Python) – Send money to anyone on the Internet
  
  
• Gilt (JavaScript) – Get access to products available for sale on Gilt.com

From the other side of the fence, if you have an API that you want to encourage other people to use consider putting a set of exercises about it on Codeacademy. Not only does it motivate learning by awarding points and badges, it has built a supportive community of users who are keen to expand their programming skills.