Devise - Flexible and modular authentication solution.
OmniAuth - Flexible authentication solution for multi-provider auth (e.g. Sign in with GitHub or Google).
Pundit - Minimal authorization through OO design and pure Ruby classes.
job-iteration - Make background jobs interruptible and resumable by design.
countries - All sorts of useful information about every country packaged as convenient little country objects. It includes data from ISO 3166 (countries and states/subdivisions ), ISO 4217 (currency), and E.164 (phone numbers).
ActiveMerchant - Payment abstraction library extracted from Shopify.
rails_event_store - A Ruby implementation of an Event Store based on Active Record.
sequent - CQRS & event sourcing framework for Ruby.
Eventide - Microservices, Autonomous Services, Service-Oriented Architecture, and Event Sourcing Toolkit for Ruby with Support for Event Store and Postgres.
Enumerize - Enumerated attributes with I18n and ActiveRecord/Mongoid/MongoMapper/Sequel support.
paranoia - Overriding ActiveRecord
destroy to act as soft deletion.
scenic - Versioned database views for Rails.
audited - An ORM extension that logs all changes to your Rails models.
paper_trail - Track changes to your models, for auditing or versioning. See how a model looked at any stage in its lifecycle, revert it to any version, or restore it after it has been destroyed.
globalize - Rails I18n de-facto standard library for ActiveRecord model/data translation.
simple_form - Forms made easy for Rails! It's tied to a simple DSL, with no opinion on markup.
view_component - A framework for building reusable, testable & encapsulated view components in Ruby on Rails.
wicked_pdf - PDF generator (from HTML) plugin for Ruby on Rails.
Bullet - Helps to kill N+1 queries and unused eager loading.