How do I send emails from a Rails app?

In Rails, you typically send email with Action Mailer, which is built into Rails.

1. Create a mailer

Generate one with:

rails generate mailer UserMailer

This creates:

• app/mailers/user_mailer.rb
• app/views/user_mailer/
• test files

2. Define an email method

Example:

# app/mailers/user_mailer.rb
class UserMailer < ApplicationMailer
  def welcome_email(user)
    @user = user
    mail(to: @user.email, subject: "Welcome to My App")
  end
end

3. Create the email view

Rails will look for a view matching the method name:

<!-- app/views/user_mailer/welcome_email.html.erb -->
<h1>Welcome, <%= @user.name %>!</h1>
<p>Thanks for signing up.</p>

You can also create a text version:

<!-- app/views/user_mailer/welcome_email.text.erb -->
Welcome, <%= @user.name %>!
Thanks for signing up.

4. Send the email

From a controller, job, or anywhere in your app:

UserMailer.welcome_email(@user).deliver_now

Or asynchronously:

UserMailer.welcome_email(@user).deliver_later

5. Configure delivery settings

You need to configure a mail delivery method in your environment files.

Example for SMTP in config/environments/production.rb:

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address: "smtp.gmail.com",
  port: 587,
  user_name: ENV["SMTP_USERNAME"],
  password: ENV["SMTP_PASSWORD"],
  authentication: :login,
  enable_starttls_auto: true
}
config.action_mailer.default_url_options = { host: "yourdomain.com" }

For development, you might use a tool like letter_opener or mailcatcher to preview emails instead of sending real ones.

6. Set defaults in ApplicationMailer

# app/mailers/application_mailer.rb
class ApplicationMailer < ActionMailer::Base
  default from: "no-reply@yourdomain.com"
  layout "mailer"
end

---

Example: full flow

# app/models/user.rb
class User < ApplicationRecord
end

# app/mailers/user_mailer.rb
class UserMailer < ApplicationMailer
  def welcome_email(user)
    @user = user
    mail(to: @user.email, subject: "Welcome!")
  end
end

# app/controllers/users_controller.rb
class UsersController < ApplicationController
  def create
    @user = User.create!(user_params)
    UserMailer.welcome_email(@user).deliver_later
    redirect_to root_path, notice: "Account created!"
  end
end

If you want, I can also show you:

• how to send emails with Devise
• how to set up SMTP with Gmail/SendGrid
• how to build HTML + text multipart emails
• how to send emails from background jobs