Ruby Academy · Lesson

Creating Your Own Gem

Build and publish your own Ruby gem for others to use.

Lesson 4 of 410 steps

Creating Your Own Gem is a free Ruby Academy lesson on CoddyKit. This is lesson 4 of 4. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the Ruby Academy learning path, and your progress syncs across the web and the CoddyKit app. The Ruby Academy course includes 4 lessons in total.

Building Your Own Gem

Creating Your Own Gem

Ruby allows developers to create their own reusable libraries, called gems.

In this lesson, you will learn how to build and publish a Ruby gem.

Starting a New Gem Project

Use Bundler to generate a new gem structure:

bundle gem my_gem

Understanding Gem File Structure

A generated gem project includes:

lib/: Contains the main gem code.
my_gem.gemspec: Defines gem metadata.
Rakefile: Used for automation tasks.

Writing Gem Code

Edit the lib/my_gem.rb file to define the gem’s functionality.

module MyGem
  def self.hello
    'Hello from MyGem!'
  end
end

Editing the .gemspec File

The my_gem.gemspec file contains metadata about your gem.

Gem::Specification.new do |spec|
  spec.name        = 'my_gem'
  spec.version     = '0.1.0'
  spec.summary     = 'A simple example gem'
  spec.authors     = ['Your Name']
  spec.files       = Dir['lib/**/*.rb']
end

Building the Gem

Run the following command to create a gem package:

gem build my_gem.gemspec

Installing and Testing Your Gem Locally

Install your gem locally before publishing:

gem install ./my_gem-0.1.0.gem

Publishing Your Gem to RubyGems.org

To publish your gem, first authenticate and then push the gem:

gem push my_gem-0.1.0.gem

Congratulations!

You have learned how to create and publish your own Ruby gem.

This concludes the 'Working with Gems and Bundler' section.

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Frequently Asked Questions

Is the “Creating Your Own Gem” lesson free?

Yes — any 3 lessons of the Ruby Academy learning path, including “Creating Your Own Gem”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The Ruby Academy course includes 4 lessons in total.

What will I learn in “Creating Your Own Gem”?

Build and publish your own Ruby gem for others to use. You practise Ruby Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Ruby Academy?

No prior experience is required. Ruby Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 4 of 4.

How long does the “Creating Your Own Gem” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Ruby Academy lesson?

Yes. Every Ruby Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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