01One wp_mail(), a chain of connections
The send is taken over completely rather than the mailer being reconfigured, so when a connection refuses the message the next one is tried on the same request. The whole chain is one row in the log, not three — a single email should not read as three separate failures.
02It tries again later, not just louder
When every connection has failed the message is queued and tried again after one minute, five minutes and thirty minutes. Three attempts and it stops: an address that does not exist will not start existing on the fortieth try.
03The log is yours and stays yours
Recipient, subject, status, the provider’s own reply and the attempt count are written to a table in your database. Nothing about your email is sent to us. Keeping the body is a setting, so on a site where the body is personal data you can keep the log and drop the content.
04Installed and unconfigured, it changes nothing
With no connection defined the filter hands the send straight back to WordPress. A plugin that swallowed a store’s email while somebody worked out the settings would be worse than the problem it set out to solve.
05Which plugin sent it
A message can carry a source label — a form, a recovery email, a WooCommerce notification — that is recorded in its own column and taken off the message before it goes out. The label tells you where the email came from without ever reaching the person who receives it.
06More providers are being added
Generic SMTP and PHP mail() are written today. Brevo, SendGrid, Mailgun, Postmark, SparkPost, Elastic Email, SMTP2GO and Resend come next, each over its own API and each behind the same connection screen.
07Delivery status on the order
The WooCommerce link is designed and not yet written: an order’s emails will be tied to the order itself, so the order screen can answer whether the confirmation reached the customer — and send it again from there.
08What it will never be
Not a newsletter tool and not a sending service. There is no plan to move your email content onto our machines, because the reason to install this is that it does not.