# Rails (SMTP) > Send email from Rails through MailBlastr using Action Mailer over SMTP. Rails' Action Mailer sends over SMTP. Configure its `smtp_settings` to use the MailBlastr relay and authenticate with your API key — then send mailers as usual. SMTP sends appear in your dashboard and event log just like API sends. ## Prerequisites - A MailBlastr [API key](https://www.mailblastr.com/docs/api-keys/overview). - A [verified domain](https://www.mailblastr.com/docs/domains/managing) to send from. ## 1. Configure your environment Add these lines to your environment config file, reading the API key from `ENV`. **config/environments/production.rb** ```rb config.action_mailer.delivery_method = :smtp config.action_mailer.smtp_settings = { :address => 'smtp.mailblastr.com', :port => 465, :user_name => 'mailblastr', :password => ENV['MAILBLASTR_API_KEY'], :tls => true } ``` ## 2. Create a mailer Define a `UserMailer`. The `default from:` must be on a domain verified with MailBlastr. **app/mailers/user_mailer.rb** ```rb class UserMailer < ApplicationMailer default from: 'Acme ' # this domain must be verified with MailBlastr def welcome_email @user = params[:user] @url = 'http://example.com/login' mail(to: ["delivered@example.com"], subject: 'hello world') end end ``` And create the matching ERB email template. **app/views/user_mailer/welcome_email.html.erb** ```html

Welcome to example.com, <%= @user.name %>

You have successfully signed up to example.com,

To log in to the site, just follow this link: <%= @url %>.

Thanks for joining and have a great day!

``` ## 3. Send the email Build the mailer instance and deliver it. ```rb u = User.new name: "derich" mailer = UserMailer.with(user: u).welcome_email mailer.deliver_now! ``` > **Note:** Use port `587` with `:enable_starttls_auto => true` instead of `:tls => true` to send over STARTTLS. See [Send an email](https://www.mailblastr.com/docs/api/emails-send) for the HTTP API.