Posted almost 3 years ago. Visible to the public.

Where to find API documentation

There is no single place to look up documentation for our stack. Google is your friend here.

This card includes some hints where you can find API documentation. You probably want to drag a few of those links to your bookmarks toolbar. This will help in the upcoming exercises.


A good Ruby documentation is

The homepage of is a little confusing. Here are docs for Ruby 2.2.2.

If you want to have docs for various Ruby/Rails versions try

Ruby on Rails

Since you will use Rails more than any other gem, you will always want its documentation to be close:

Note that ActiveSupport extends core classes in Ruby .
We are so used to having ActiveSupport around that we don’t even think of it separate from Ruby anymore.
Which is why some methods you would expected to be documented in Ruby are actually in the Rails cos, e.g.


The best way to learn about a Ruby gem, Javascript libary, etc. is often to find the repository on Github and look at its README file. Here are a few examples:

Some libraries also publish dedicated sites with their documentation, e.g.:

There are a few sites that try to make available documentation for most Rubygems under a common interface:

External APIs

When you're using external SaaS APIs, they often publish language-independent documentation. Some examples:

Owner of this card:

Henning Koch
Last edit:
10 months ago
by Henning Koch
Posted by Henning Koch to makandra Curriculum
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