Ruby Knowledge

Authoritative resource map for Ruby development. Use these sources rather than searching broadly.

Never use these sources:

• ruby-doc.org
• apidock.com

Official Documentation

Primary source: https://docs.ruby-lang.org/en/

Other Useful Resources

• https://rubyreferences.github.io/rubychanges/ - Version-by-version changelog with examples
• https://railsatscale.com/ - Shopify engineering blog (Latest updates on Ruby and its toolings)

Core & Standard Library

Term	Meaning
Default gem	Ships with Ruby, cannot uninstall
Bundled gem	Ships with Ruby, can uninstall/replace
Standard library	Part of Ruby itself, not a gem

To check which gem versions ship with each Ruby release: https://stdgems.org/

Version	Documentation	Standard Library
3.2	https://docs.ruby-lang.org/en/3.2/	https://docs.ruby-lang.org/en/3.2/standard_library_rdoc.html
3.3	https://docs.ruby-lang.org/en/3.3/	https://docs.ruby-lang.org/en/3.3/standard_library_rdoc.html
3.4	https://docs.ruby-lang.org/en/3.4/	https://docs.ruby-lang.org/en/3.4/standard_library_md.html
4.0	https://docs.ruby-lang.org/en/4.0/	https://docs.ruby-lang.org/en/4.0/standard_library_md.html
master	https://docs.ruby-lang.org/en/master/	https://docs.ruby-lang.org/en/master/standard_library_md.html

Testing Frameworks

Framework	GitHub	Documentation
minitest	https://github.com/minitest/minitest	https://docs.seattlerb.org/minitest/
test-unit	https://github.com/test-unit/test-unit	https://test-unit.github.io/

Typing Ecosystem

Two type definition formats exist in Ruby:

• RBI - Sorbet's format. Uses Ruby DSL syntax (sig { ... }) in .rb and .rbi files.
• RBS - Official Ruby format (Ruby 3.0+). Dedicated syntax in .rbs files or inline as comments.

Sorbet Ecosystem

Sorbet is a static and runtime type checker for Ruby, maintained by Stripe. Key companion tools:

• Tapioca - Generates RBI files for gems and DSLs (Rails, ActiveRecord, etc.)
• Spoom - Coverage analysis, strictness bumping, dead code detection, signature migration

RBS Ecosystem

• rbs - Official CLI for working with RBS files (prototype, list, methods)
• Steep - Type checker that uses RBS

RBS Inline Comments

Sorbet supports RBS-style inline type annotations using #: comment syntax. This eliminates the need for separate .rbi files or verbose sig blocks.

Docs: https://sorbet.org/docs/rbs-comments