Chatwoot/config/initializers/mailer.rb

Rails.application.configure do
  #########################################
  # Configuration Related to Action Mailer
  #########################################

  # We need the application frontend url to be used in our emails
  config.action_mailer.default_url_options = { host: ENV['FRONTEND_URL'] } if ENV['FRONTEND_URL'].present?
  # We load certain mailer templates from our database. This ensures changes to it is reflected immediately
  config.action_mailer.perform_caching = false
  config.action_mailer.perform_deliveries = true
  config.action_mailer.raise_delivery_errors = true

  # Config related to smtp
  smtp_settings = {
    address: ENV.fetch('SMTP_ADDRESS', 'localhost'),
    port: ENV.fetch('SMTP_PORT', 587)
  }

  smtp_settings[:authentication] = ENV.fetch('SMTP_AUTHENTICATION', 'login').to_sym if ENV['SMTP_AUTHENTICATION'].present?
  smtp_settings[:domain] = ENV['SMTP_DOMAIN'] if ENV['SMTP_DOMAIN'].present?
  smtp_settings[:user_name] = ENV.fetch('SMTP_USERNAME', nil)
  smtp_settings[:password] = ENV.fetch('SMTP_PASSWORD', nil)
  smtp_settings[:enable_starttls_auto] = ActiveModel::Type::Boolean.new.cast(ENV.fetch('SMTP_ENABLE_STARTTLS_AUTO', true))
  smtp_settings[:openssl_verify_mode] = ENV['SMTP_OPENSSL_VERIFY_MODE'] if ENV['SMTP_OPENSSL_VERIFY_MODE'].present?
  smtp_settings[:ssl] = ActiveModel::Type::Boolean.new.cast(ENV.fetch('SMTP_SSL', true)) if ENV['SMTP_SSL']
  smtp_settings[:tls] = ActiveModel::Type::Boolean.new.cast(ENV.fetch('SMTP_TLS', true)) if ENV['SMTP_TLS']

  config.action_mailer.delivery_method = :smtp unless Rails.env.test?
  config.action_mailer.smtp_settings = smtp_settings
  # You can use letter opener for your local development by setting the environment variable
  config.action_mailer.delivery_method = :letter_opener if Rails.env.development? && ENV['LETTER_OPENER']

  # Use sendmail if using postfix for email
  config.action_mailer.delivery_method = :sendmail if ENV['SMTP_ADDRESS'].blank?

  #########################################
  # Configuration Related to Action MailBox
  #########################################

  # Set this to appropriate ingress service for which the options are :
  # :relay for Exim, Postfix, Qmail
  # :mailgun for Mailgun
  # :mandrill for Mandrill
  # :postmark for Postmark
  # :sendgrid for Sendgrid
  config.action_mailbox.ingress = ENV.fetch('RAILS_INBOUND_EMAIL_SERVICE', 'relay').to_sym
end