Delivery lifecycle

Hook	Kind	Tier	Since	Summary
boolean_smtp_email_delivery_failed_final	action	A	1.0.0	Fires when a mail delivery attempt has failed with no further fallback to try.
boolean_smtp_email_event_data	filter	A	1.0.0	Filters the data describing a mail delivery event before it is announced and used to build a notification.
boolean_smtp_email_failed	action	A	1.0.0	Fires after a send attempt has failed, before the fallback connection is tried.
boolean_smtp_email_log_deleted	action	B	1.0.0	Fires after an email log entry has been deleted.
boolean_smtp_email_logged	action	B	1.0.0	Fires after an email log entry has been created.
boolean_smtp_email_queued	action	A	1.0.0	Fires after an email has been added to the queue.
boolean_smtp_email_sent	action	A	1.0.0	Fires after a message has been delivered successfully.
boolean_smtp_log_retention_days	filter	A	1.0.0	Filters the number of days email logs are kept before the daily cleanup removes them.
boolean_smtp_process_queue	action (WP-Cron)	B	1.0.0	Fires every minute while the email queue is enabled; each run sends one batch of queued messages.
boolean_smtp_prune_logs	action (WP-Cron)	B	1.0.0	Fires daily; each run deletes the email log entries older than the retention period.
boolean_smtp_queue_batch_size	filter	B	1.0.0	Filters how many queued messages one worker run sends.
boolean_smtp_should_notify_delivery_failure	filter	A	1.0.0	Filters whether a final delivery failure is announced and notified.
boolean_smtp_should_store_smtp_transcript	filter	B	1.0.0	Filters whether the SMTP transcript of a send is stored as a debug session file.
boolean_smtp_simulation_captured	action	A	1.0.0	Fires after a message has been captured by Email Simulation Mode instead of being sent.
boolean_smtp_test_email_sent	action	A	1.0.0	Fires after the admin test-email tool has attempted a send.