I started using Mailgun recently - and I wasn't aware that you had this as a feature, or I would have been using it.

The only use case you really market is as an API. At least that I've been exposed to, across several channels, after actively investigating which ESP I wanted to use, after actively paying attention to marketing from you and your main competitors for several years. So...yeah.

I can find documentation easily enough now that I know to check the docs for it, but maybe it's more an issue with publicizing this aspect of the service?