Action Mailer
Action Mailer allows you to send emails from your Rails application. It works like controllers but for emails instead of web responses.
Creating a Mailer
bash
1rails generate mailer UserMailer welcome password_resetThis creates:
app/mailers/user_mailer.rbapp/views/user_mailer/welcome.html.erbapp/views/user_mailer/welcome.text.erbapp/views/user_mailer/password_reset.html.erbapp/views/user_mailer/password_reset.text.erb
Basic Mailer
ruby
1# app/mailers/user_mailer.rb
2class UserMailer < ApplicationMailer
3 def welcome(user)
4 @user = user
5 @login_url = login_url
6
7 mail(
8 to: @user.email,
9 subject: "Welcome to Our App!"
10 )
11 end
12
13 def password_reset(user)
14 @user = user
15 @reset_url = password_reset_url(token: @user.reset_token)
16
17 mail(
18 to: @user.email,
19 subject: "Password Reset Instructions"
20 )
21 end
22endEmail Templates
HTML Template
erb
1<!-- app/views/user_mailer/welcome.html.erb -->
2<!DOCTYPE html>
3<html>
4<head>
5 <style>
6 .container { max-width: 600px; margin: 0 auto; font-family: Arial, sans-serif; }
7 .header { background: #4F46E5; color: white; padding: 20px; text-align: center; }
8 .content { padding: 20px; }
9 .button {
10 display: inline-block;
11 background: #4F46E5;
12 color: white;
13 padding: 12px 24px;
14 text-decoration: none;
15 border-radius: 4px;
16 }
17 .footer { padding: 20px; text-align: center; color: #666; font-size: 12px; }
18 </style>
19</head>
20<body>
21 <div class="container">
22 <div class="header">
23 <h1>Welcome to Our App!</h1>
24 </div>
25 <div class="content">
26 <p>Hi <%= @user.name %>,</p>
27 <p>Thanks for signing up! We're excited to have you on board.</p>
28 <p>Click the button below to get started:</p>
29 <p>
30 <a href="<%= @login_url %>" class="button">Log In Now</a>
31 </p>
32 <p>If you have any questions, just reply to this email.</p>
33 <p>Cheers,<br>The Team</p>
34 </div>
35 <div class="footer">
36 <p>© <%= Date.current.year %> Our App. All rights reserved.</p>
37 </div>
38 </div>
39</body>
40</html>Text Template
erb
1<!-- app/views/user_mailer/welcome.text.erb -->
2Welcome to Our App!
3==================
4
5Hi <%= @user.name %>,
6
7Thanks for signing up! We're excited to have you on board.
8
9Get started by logging in:
10<%= @login_url %>
11
12If you have any questions, just reply to this email.
13
14Cheers,
15The Team
16
17--
18© <%= Date.current.year %> Our App. All rights reserved.Sending Emails
Send Immediately
ruby
1# Sends synchronously (blocks the request)
2UserMailer.welcome(@user).deliver_nowSend in Background (Recommended)
ruby
1# Queues for background processing
2UserMailer.welcome(@user).deliver_later
3
4# With delay
5UserMailer.welcome(@user).deliver_later(wait: 1.hour)
6
7# At specific time
8UserMailer.welcome(@user).deliver_later(wait_until: Date.tomorrow.noon)Mail Options
ruby
1class UserMailer < ApplicationMailer
2 def notification(user, subject:, body:)
3 @user = user
4 @body = body
5
6 mail(
7 to: @user.email,
8 from: "notifications@example.com",
9 cc: "admin@example.com",
10 bcc: "logs@example.com",
11 reply_to: "support@example.com",
12 subject: subject
13 )
14 end
15
16 def with_attachment(user, document)
17 @user = user
18
19 # Attach file
20 attachments['document.pdf'] = File.read(document.path)
21
22 # Attach with options
23 attachments['report.csv'] = {
24 mime_type: 'text/csv',
25 content: generate_csv
26 }
27
28 # Inline attachment (for images in HTML)
29 attachments.inline['logo.png'] = File.read('app/assets/images/logo.png')
30
31 mail(to: @user.email, subject: 'Your Document')
32 end
33endUsing inline attachments in HTML:
erb
1<%= image_tag attachments['logo.png'].url %>Configuration
Development (Letter Opener)
ruby
1# Gemfile
2gem 'letter_opener', group: :development
3
4# config/environments/development.rb
5config.action_mailer.delivery_method = :letter_opener
6config.action_mailer.perform_deliveries = trueProduction (SMTP)
ruby
1# config/environments/production.rb
2config.action_mailer.delivery_method = :smtp
3config.action_mailer.smtp_settings = {
4 address: 'smtp.example.com',
5 port: 587,
6 domain: 'example.com',
7 user_name: ENV['SMTP_USERNAME'],
8 password: ENV['SMTP_PASSWORD'],
9 authentication: 'plain',
10 enable_starttls_auto: true
11}SendGrid
ruby
1config.action_mailer.smtp_settings = {
2 address: 'smtp.sendgrid.net',
3 port: 587,
4 domain: 'yourdomain.com',
5 user_name: 'apikey',
6 password: ENV['SENDGRID_API_KEY'],
7 authentication: :plain,
8 enable_starttls_auto: true
9}Postmark
ruby
1# Gemfile
2gem 'postmark-rails'
3
4# config/environments/production.rb
5config.action_mailer.delivery_method = :postmark
6config.action_mailer.postmark_settings = {
7 api_token: ENV['POSTMARK_API_TOKEN']
8}Application Mailer
Set defaults for all mailers:
ruby
1# app/mailers/application_mailer.rb
2class ApplicationMailer < ActionMailer::Base
3 default from: 'notifications@example.com',
4 reply_to: 'support@example.com'
5
6 layout 'mailer'
7
8 # Helper methods available to all mailers
9 helper :application
10
11 private
12
13 def user_email(user)
14 mail(to: email_address_with_name(user.email, user.name))
15 end
16endEmail Layout
erb
1<!-- app/views/layouts/mailer.html.erb -->
2<!DOCTYPE html>
3<html>
4<head>
5 <meta content="text/html; charset=UTF-8" http-equiv="Content-Type" />
6 <style>
7 /* Global email styles */
8 body { font-family: Arial, sans-serif; line-height: 1.6; }
9 </style>
10</head>
11<body>
12 <%= yield %>
13</body>
14</html>Callbacks
ruby
1class UserMailer < ApplicationMailer
2 before_action :set_user
3 after_action :log_delivery
4
5 def welcome
6 mail(to: @user.email, subject: 'Welcome!')
7 end
8
9 private
10
11 def set_user
12 @user = params[:user]
13 end
14
15 def log_delivery
16 Rails.logger.info "Sending #{action_name} email to #{@user.email}"
17 end
18end
19
20# Using with params
21UserMailer.with(user: @user).welcome.deliver_laterPreview Emails
ruby
1# test/mailers/previews/user_mailer_preview.rb
2class UserMailerPreview < ActionMailer::Preview
3 def welcome
4 user = User.first || User.new(name: 'Test', email: 'test@example.com')
5 UserMailer.welcome(user)
6 end
7
8 def password_reset
9 user = User.first
10 UserMailer.password_reset(user)
11 end
12endView at: http://localhost:3000/rails/mailers/user_mailer/welcome
Action Mailer makes sending beautiful emails from Rails straightforward!