Bootbox is used to show modals and alerts. You can test it by running bootbox.alert('hello') in your browser console.
@julian Do you engage in a more intimate relationship with Haraka?
Niche third party platforms would be far less likely. Postfix is built into nearly all production platforms and configured out of the box for most usages (standard SMTP relay.) His point was that they don't get their hands dirty with any specific email implementation and leave that for the admins, they just send email out on whatever protocol or API is selected and the rest is up to the email admin to configure.