Sending email is integral part of every web application nowadays. In this post we will cover how to send emails from a rails application.

First you need an active smtp server to send an email, because only SMTP servers are capable of sending or receiving emails. There are many providers such as gmail, sendgrid and more. For this post, we will consider using gmail.

Assuming you have a Rails application with User model.

1. We need to configure SMTP server. This can be set in config/environments/development.rb

      config.action_mailer.delivery_method = :smtp
      host = 'example.com' #replace with your own url
      config.action_mailer.default_url_options = { host: host }
       
      # SMTP settings for gmail
      config.action_mailer.smtp_settings = {
          :address              => "smtp.gmail.com",
          :port                 => 587,
          :user_name            => ENV['EMAIL'],
          :password             => ENV['PASSWORD'],
          :authentication       => "plain",
          :enable_starttls_auto => true
      }
   

2. Lets write the code now. What will be sent in the email? Let’s say we want to send a welcome mail when user signs up. We will generate a mailer named - rails g mailer UserRegistration
   This will generate

3. Open app/mailers/user_registrations_mailer.rb and add method following method

   def registration(user)
    @user = user
    mail(to: user.email, subject: 'Welcome to Rails learning')
   end
   

4. Open app/views/user_registrations_mailer & add a new .erb file whose name resembles with method name in app/mailers/user_registrations_mailer.rb. In our case it is registration.html.erb, now put in whatever welcome message you want a user to see in email. I will simply add

    Hello <%= @user.first_name%> <%= @user.last_name %>,
       
    Welcome to Ruby on Rails learning.
       
    Thanks for signing up.
   

5. We need to trigger the action of sending emails. There are multiple ways to achieve this. Can call this from controller action or a service call or activerecord callback. Will prefer last option here In User model register after_create callback

    after_create :send_sign_up_email
    .
    .
    .
    private
    def user_registration_email
      UserRegistrationsMailer.registration(self).deliver_now
    end
   

And now you are all set to send sign-up emails.