We are using Mailgun as our primary mailing service, and as we are currently rebranding, we are also heavily monitoring the delivery of our emails. To help with this, Mailgun as the ability to “tag” a type of email being sent so it can classify the number of emails being sent per category, associated with delivery/complaints, opens and clicks. Those are not (yet!) metrics being surfaced by Courier.
The tags that are currently being shown are from a third-party sending emails directly through Mailgun (in our case, Chargebee).
Having those tag for each email being sent through Courier would be very valuable, to expose on Mailgun the success of our emails on Mailgun.
What it would take is to add to Mailgun a tag attribute for every email that is being sent, that can be named after the event (more stable than a possible notification name?).
This is the link to Mailgun’s documentation on tagging: User Manual — Mailgun API documentation