action-mailer

To send emails with Rails Action Mailer, you generate a mailer class, create corresponding HTML and text templates, configure SMTP delivery methods, and use `deliver_later` for asynchronous execution. This ensures reliable email delivery from your application.

SMTP delivery methods for Rails email templates are configured within environment-specific files, allowing distinct setups for test, development, and production. You define SMTP server details and authentication parameters to ensure mailers route messages correctly across environments.

The best way to test Rails mailers is by writing comprehensive tests that verify email content and delivery, alongside using built-in previews for rapid visual iteration. Previews let you inspect HTML and text email templates without sending actual emails.

Action Mailer supports parameterized mailers for cleaner code organization and asynchronous delivery using `deliver_later`. This approach improves application performance by offloading email sending tasks to background jobs.

Broken links in Rails email templates often occur when `default_url_options` are not set, preventing the generation of absolute URLs. Setting host configurations for each environment ensures links resolve correctly outside the web application context.