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send email with ruby on rails

How to Send Email with Ruby on Rails in 5 Minutes

—

by

ian
in

Last Updated on August 4, 2026 by ian

Rails has Action Mailer built in. It’s one of the most complete email systems in any framework. This guide shows you how to configure ConvertNow as your Action Mailer delivery method, create mailers, use ERB templates, and handle common production patterns.

Step 1: Configure Action Mailer

Add SMTP settings to config/environments/production.rb:

# config/environments/production.rb
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address:              'out.convertnow.co',
  port:                 465,
  ssl:                  true,   # implicit SSL on port 465
  user_name:            ENV['MAIL_USERNAME'],
  password:             ENV['CONVERTNOW_API_KEY'],
  authentication:       :plain,
  enable_starttls_auto: false,  # not needed with implicit SSL
}
config.action_mailer.default_url_options = { host: 'myapp.com' }

Set your environment variables:

[email protected]
CONVERTNOW_API_KEY=cn_live_YOUR_KEY

Step 2: Generate a mailer

Use Rails’ generator to create your first mailer:

rails generate mailer UserMailer welcome_email password_reset

This creates app/mailers/user_mailer.rb and view templates in app/views/user_mailer/:

# app/mailers/user_mailer.rb
class UserMailer < ApplicationMailer
  default from: '[email protected]'

  def welcome_email
    @user = params[:user]
    mail(
      to: @user.email,
      subject: "Welcome to MyApp, #{@user.name}!"
    )
  end

  def password_reset
    @user  = params[:user]
    @token = params[:token]
    mail(
      to: @user.email,
      subject: 'Reset your password'
    )
  end
end

Step 3: Create ERB email templates

Create app/views/user_mailer/welcome_email.html.erb:

<!DOCTYPE html>
<html>
<body>
  <h1>Hi <%= @user.name %>!</h1>
  <p>Your account is ready.</p>
  <p><%= link_to 'Log in to your account', login_url %></p>
</body>
</html>

Create the plain-text version app/views/user_mailer/welcome_email.text.erb:

Hi <%= @user.name %>!

Your account is ready.

Log in here: <%= login_url %>

Step 4: Send the email from a controller

# app/controllers/users_controller.rb
class UsersController < ApplicationController
  def create
    @user = User.new(user_params)

    if @user.save
      # Send welcome email
      UserMailer.with(user: @user).welcome_email.deliver_now

      render json: { message: 'Account created' }, status: :created
    else
      render json: { errors: @user.errors }, status: :unprocessable_entity
    end
  end
end

Step 5: Queue emails with Active Job

deliver_now blocks the request thread. Use deliver_later in production so emails are processed in the background:

# In your controller or model callback:
UserMailer.with(user: @user).welcome_email.deliver_later

# With a delay:
UserMailer.with(user: @user).welcome_email.deliver_later(wait: 5.minutes)

# At a specific time:
UserMailer.with(user: @user).welcome_email.deliver_later(wait_until: Date.tomorrow.noon)

Configure Active Job to use Sidekiq in production (recommended):

# config/application.rb
config.active_job.queue_adapter = :sidekiq

Step 6: Send with attachments

def invoice_email
  @user    = params[:user]
  @invoice = params[:invoice]

  attachments['invoice.pdf'] = {
    mime_type: 'application/pdf',
    content:   File.read(Rails.root.join('storage', 'invoices', @invoice.filename))
  }

  mail(
    to:      @user.email,
    subject: "Your invoice ##{@invoice.number}"
  )
end

Step 7: Send to multiple recipients with CC and BCC

def team_notification
  @team = params[:team]

  mail(
    to:      @team.members.map(&:email),
    cc:      @team.manager.email,
    bcc:     '[email protected]',
    subject: 'Team update'
  )
end

Testing mailers in development

In development, use the :test delivery method to capture emails without sending:

# config/environments/development.rb
config.action_mailer.delivery_method = :test

# Emails are available in ActionMailer::Base.deliveries array
ActionMailer::Base.deliveries.last

Or use Letter Opener gem to open emails in a browser automatically:

# Gemfile
gem 'letter_opener', group: :development

# config/environments/development.rb
config.action_mailer.delivery_method = :letter_opener


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