Mail pipeline

Hook	Kind	Tier	Since	Summary
boolean_smtp_before_send	action	A	1.0.0	Fires immediately before a message is sent, after the connection and transport have been configured.
boolean_smtp_email_headers	filter	A	1.0.0	Filters the custom headers collected from PHPMailer before the message is logged.
boolean_smtp_mail_after_validate	action	A	1.0.0	Fires after a message has passed validation, before headers are normalized.
boolean_smtp_mail_attempt_recorded	action	B	1.0.0	Fires after a send attempt has been recorded in the email log.
boolean_smtp_mail_before_log	action	B	1.0.0	Fires before an outgoing message is offered to the email log.
boolean_smtp_mail_before_phpmailer	action	A	1.0.0	Fires after PHPMailer has been built from the message, before phpmailer_init runs.
boolean_smtp_mail_connection_resolved	action	A	1.0.0	Fires after a connection has been resolved for an outgoing message, before it is applied to PHPMailer.
boolean_smtp_mail_fallback	action	A	1.0.0	Fires before a failed send is retried through the fallback connection.
boolean_smtp_mail_headers	filter	A	1.0.0	Filters the header bag built from the message before normalization.
boolean_smtp_mail_headers_normalized	action	B	1.0.0	Fires after headers have been normalized, before they are written back onto the message.
boolean_smtp_mail_intake	action	A	1.0.0	Fires when a message enters the BooleanSMTP mail pipeline, before validation runs.
boolean_smtp_mail_send_result	action	A	1.0.0	Fires after a send attempt has completed, whether it succeeded or failed.
boolean_smtp_mail_transport_send	action	B	1.0.0	Fires immediately before the message is handed to PHPMailer's transport.
boolean_smtp_mail_validate	filter	A	1.0.0	Filters whether a message should be rejected before it is processed further.
boolean_smtp_mailer_resolved	action	B	1.0.0	Fires after the mailer has been fully configured for a send, with diagnostic details about the resolved connection and transport.
boolean_smtp_max_retry_attempts	filter	A	1.0.0	Filters how many times a failed message is retried on other connections.
boolean_smtp_message_body	filter	A	1.0.0	Filters the message body immediately before it is sent.
boolean_smtp_plain_text_body	filter	A	1.0.0	Filters the automatically generated plain-text alternative body.
boolean_smtp_queue_should_enqueue	filter	A	1.0.0	Filters whether a message is queued for background delivery instead of being sent now.
boolean_smtp_resolve_connection	filter	A	1.0.0	Filters the connection resolved for an outgoing message, after routing rules and sender matching have run.
boolean_smtp_resolve_routing_rule_connection	filter	A	1.0.0	Filters the connection a routing rule resolves for an outgoing message.
boolean_smtp_should_log_email	filter	A	1.0.0	Filters whether a message is written to the email log.
boolean_smtp_skip_fallback_retry	filter	A	1.0.0	Filters whether the fallback retry should be skipped for a failed send.
boolean_smtp_transports	filter	A	1.0.0	Filters the map of registered transport drivers.