Open-source development tools for Ruby on Rails. UI components and generators extracted from production applications — not theoretical exercises.

maquina.app — Generators, Components, MCP Server, Claude Skills

Every Rails app starts the same way

After rails new, you always end up doing the same setup:

The Maquina ecosystem

$ rails g maquina:app --auth registration

$ rails g maquina_components:install

Available generators

The orchestrator: maquina:app

One command that runs all generators and sets up your entire application.

$ rails g maquina:app --auth registration

01 Create the Rails app

$ rails new myapp --css tailwind
$ cd myapp

Rails 8 gives you sensible defaults out of the box:

You can already run bin/dev and visit http://localhost:3000

02 Add Maquina generators

$ bundle add maquina_generators --group development

Then run the app generator with your chosen authentication:

$ rails generate maquina:app --auth registration

This is a development-only gem. Generated code lives entirely in your app — no runtime dependency. Delete the gem after running.

02 What the generator does

$ bin/rails generate solid_errors:install
# decline the initializer overwrite

$ bin/rails db:migrate

$ bin/rails credentials:edit
# set backstage username/password

$ bin/dev

03 The registration generator

Builds on top of Rails 8's generate authentication, which gives you login but no signup.

03 Key generated files

class Account < ApplicationRecord
  has_many :users, dependent: :destroy

  validates :name, presence: true
end

class User < ApplicationRecord
  has_secure_password
  has_many :sessions, dependent: :destroy
  belongs_to :account

  validates :name, presence: true

  enum :role,
    {member: "member", admin: "admin"},
    default: "member"
end

class Current < ActiveSupport::CurrentAttributes
  attribute :session
  delegate :user, to: :session, allow_nil: true
  delegate :account, to: :user, allow_nil: true
end

# In any controller or view:
Current.user     # logged-in user
Current.account  # user's account
Current.user.admin? # role check

03 Registration flow

Creates Account + User (as admin) in a single transaction:

class RegistrationsController < ApplicationController
  allow_unauthenticated_access
  rate_limit to: 10, within: 3.minutes, only: :create

  def create
    ActiveRecord::Base.transaction do
      account = Account.create!(name: params[:account_name])
      user = account.users.create!(
        name: params[:name],
        email_address: params[:email_address],
        password: params[:password],
        role: :admin
      )
    end

    start_new_session_for user
    redirect_to root_path
  end
end

The first user who creates an account automatically becomes its admin.

03 Authentication flow

04 Your first resource

$ bin/rails generate scaffold Project name:string description:text account:references
$ bin/rails db:migrate

# app/models/account.rb
class Account < ApplicationRecord
  has_many :users, dependent: :destroy
  has_many :projects, dependent: :destroy

  validates :name, presence: true
end

# app/models/project.rb
class Project < ApplicationRecord
  belongs_to :account

  validates :name, presence: true
end

04 Multi-tenancy pattern

Always query through Current.account — users never see data from other accounts.

class ProjectsController < ApplicationController
  def index
    @projects = Current.account.projects
  end

  def create
    @project = Current.account.projects.build(project_params)

    if @project.save
      redirect_to @project
    else
      render :new, status: :unprocessable_entity
    end
  end

  private

  def set_project
    @project = Current.account.projects.find(params[:id])
    # raises RecordNotFound if project belongs to another account
  end
end

05 Role-based authorization

Use the role enum to restrict actions by user role.

class ProjectsController < ApplicationController
  before_action :require_admin, only: [:destroy]

  # ...

  private

  def require_admin
    unless Current.user.admin?
      redirect_to projects_path,
        alert: t("flash.general.forbidden")
    end
  end
end

06 The full picture