# Ruby on Rails
This example shows how to send an email for user signups. You can also checkout [this gem](https://github.com/sendgrid/sendgrid-ruby) for more advanced features.
## Setup ActionMailer
Let's generate a Mailer class. Mailer classes function as our
controllers for email views.
```bash
rails generate mailer UserNotifierMailer
```
Now we open up the mailer we've just generated, `app/mailers/user_notifier_mailer.rb` and add a mailer action that sends users a signup email.
```ruby
class UserNotifierMailer < ApplicationMailer
default :from => 'any_from_address@example.com'
# send a signup email to the user, pass in the user object that contains the user's email address
def send_signup_email(user)
@user = user
mail( :to => @user.email,
:subject => 'Thanks for signing up for our amazing app' )
end
end
```
Now we need a view that corresponds to our action and outputs HTML for our email. Create a file `app/views/user_notifier_mailer/send_signup_email.html.erb` as follows:
```html
Thanks for signing up, <%= @user.name %>!
Thanks for joining and have a great day! Now sign in and do
awesome things!
```
If you don't have a user model quite yet, generate one quickly.
```bash
rails generate scaffold user name email login
rake db:migrate
```
Now in the controller for the user model `app/controllers/users_controller.rb`, add a call to `UserNotifierMailer.send_signup_email` when a user is saved.
```ruby
class UsersController < ApplicationController
def create
# Create the user from params
@user = User.new(user_params)
if @user.save
# Deliver the signup email
UserNotifierMailer.send_signup_email(@user).deliver
redirect_to(@user, :notice => 'User created')
else
render :action => 'new'
end
end
private
def user_params
params.require(:user).permit(:name, :email, :login)
end
end
```
Alright, now we're cooking! Let's get it all going through SendGrid.
## Configure ActionMailer to Use SendGrid
In `config/environment.rb` specify your ActionMailer settings to point to SendGrid's servers.
```ruby
ActionMailer:\:Base.smtp_settings = {
:user_name => 'apikey', # This is the string literal 'apikey', NOT the ID of your API key
:password => '', # This is the secret sendgrid API key which was issued during API key creation
:domain => 'example.com',
:address => 'smtp.sendgrid.net',
:port => 587,
:authentication => :plain,
:enable_starttls_auto => true
}
```
That's it! When a new user object is saved, an email will be sent to
the user via SendGrid.
> \[!CAUTION]
>
> As a best practice, you should not store your credentials directly in the source but should instead store them in configuration files or environment variables. See this tutorial on [environment variables in Rails](https://railsapps.github.io/rails-environment-variables.html). And for Rails Versions 5.2+ see [Securely storing custom credentials in Rails.](https://guides.rubyonrails.org/security.html#custom-credentials)