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SMTP

Ruby (Mail)

Installation

Code
gem install mail

Or add to your Gemfile:

Code
gem 'mail'

Basic Configuration

Use environment variables for credentials:

Code
SMTP_HOST = 'smtp.lettermint.co'
SMTP_USERNAME = 'lettermint'
API_TOKEN = ENV['LETTERMINT_PROJECT_TOKEN']

Advanced Features

Multiple Recipients

Code
mail = Mail.new do
  from     'sender@yourdomain.com'
  to       ['user1@example.com', 'user2@example.com']
  cc       'manager@yourdomain.com'
  bcc      'archive@yourdomain.com'
  subject  'Newsletter'
  body     '<h1>Monthly Update</h1>'
end

Attachments

Code
mail = Mail.new do
  from     'sender@yourdomain.com'
  to       'recipient@example.com'
  subject  'Document Attached'
  body     'Please find the document attached.'

  add_file '/path/to/document.pdf'
  add_file filename: 'data.txt', content: 'Custom content'
end

Custom Headers

Code
mail = Mail.new do
  from     'sender@yourdomain.com'
  to       'recipient@example.com'
  subject  'Custom Headers'
  body     'Email with custom headers.'

  header['X-Priority'] = '1'
  header['X-Custom-Header'] = 'Custom Value'
end

Metadata for Tracking

Add metadata that will be included in webhook payloads:

Code
mail = Mail.new do
  from     'sender@yourdomain.com'
  to       'recipient@example.com'
  subject  'Order Confirmation'
  body     'Your order has been confirmed.'

  header['X-LM-Metadata-order_id'] = '12345'
  header['X-LM-Metadata-customer_id'] = 'cust_789'
  header['X-LM-Metadata-campaign'] = 'order_confirmation'
end

Lettermint Headers

Add Lettermint-specific headers for tags and routing:

Code
mail = Mail.new do
  from     'sender@yourdomain.com'
  to       'recipient@example.com'
  subject  'Order Confirmation'
  body     'Your order has been confirmed.'

  # Tag for categorization
  header['X-LM-Tag'] = 'order-confirmation'

  # Metadata for tracking (included in webhooks)
  header['X-LM-Metadata-order_id'] = '12345'
  header['X-LM-Metadata-customer_id'] = 'cust_789'

  # Route selection
  header['X-Lettermint-Route'] = 'transactional'
end

Rails Integration

In config/environments/production.rb:

Code
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address: 'smtp.lettermint.co',
  port: 587,
  user_name: 'lettermint',
  password: ENV['LETTERMINT_PROJECT_TOKEN'],
  authentication: 'plain',
  enable_starttls_auto: true
}