1. Following WP actions would be great additions to integrate other plugins or custom logic:
  • unconfirmed subscriber was created
  • subscriber confirmed opt-in
  • subscriber details updated
  • subscriber was added to list
  • subscriber was removed from list
  • subscriber custom field was updated
  • an email was sent to a subscriber
  • subscriber opened an email
  • subscriber clicked a link in an email
  1. And following WP filters that allow us to sanitize/modify content:
  • save custom field value to DB
  • get custom fields for manage-subscription-page (to allow us to sort/change labels or even remove fields from a form/page)
  • newsletter full body rendered (like the filter "mailpoet_rendering_post_process", but after shortcodes were rendered, with $subscriber details)
  • generate newsletter subject (allow us to customize the subject via a filter)
Note: Most of those actions aim towards the Automation feature-request and allows developers to customize the Subscriber workflow.
The Filters allow us to customize the contents of the emails, based on user interaction.
Sample use cases that I want to implement using those actions/filters:
  • User opened an email but did not click the link: I want to add an extra sentence in the next email, via the filter.
  • User was added to a list: I want to automatically generate a one-time-discount code for that user and store it in a custom field.
  • The Manage-Subscription page should not display the custom field with the discount code, as the user is not allowed to change the value.
  • User received two emails without opening them: I'd like to modify the email subject of the third email