How to use Postmark Templates & Api with Devise

my_custom_mailer.rb

# 1 - Create a custom mailer in mailers/my_cutsom_mailer.rb and inherit from Devise::Mailer add the following - replacing to suit your needs

class UserMailer < Devise::Mailer
  include PostmarkRails::TemplatedMailerMixin

  helper :application
  include Rails.application.routes.url_helpers
  include Devise::Controllers::UrlHelpers

  default from: '[email protected]'
  default reply_to: '[email protected]' # Optional 

  def confirmation_instructions(record, token, opts={})
    @admin = record
    @token = token
    # this will pass the data via the postmark-api to your template / layout these fields are 100% customizable and can be cahnged in your template / layout
    self.template_model = { product_name: 'your product',
                            username: @user.username,
                            email: @user.email,
                            confirmation_url: user_confirmation_url(@resource, confirmation_token: @token, subdomain: 'add subdomain here if needed'),
                            login_url: login_root_url(subdomain: 'add subdomain here if needed'),
                            trial_length: '14-days',
                            sender_name: 'What ever you want',
                            action_url: user_confirmation_url(@resource, confirmation_token: @token, subdomain: 'add subdomain here if needed'),
                            parent_company_name: 'Your company name',
                            company_address: 'Your address'}
    mail to: @admin.email, postmark_template_alias: 'devise_user_confirmation'
    
    # Rinse and Repeat for Password resets and Unlocks --- Ill update this gist with passowrd and unlocks in the near future
  end
end

# Note the postmark_template_alias: '' - This is important to configure! otherwize your mailers will fail. 
# You can configure it by heading to your Template / Latyouts click on your template and right above the name field you
# will find Alias: some_clickable_link, Click it and set the name to your preference and add it to your mailer file above.

user.rb

# Next step is to add a custom function to your devise user model.

class Admin < ApplicationRecord
  devise :database_authenticatable, :confirmable,
         :recoverable, :rememberable, :validatable,
         :timeoutable, :trackable

  def devise_mailer
    UserMailer
  end
end

# And thats literally all there is to it! reset your server and reload your console and have at it. (yes this will send on a valid user create from your user forms too. 
# Feel free to add any questions or comments below!