Can this software be used as an app for my non-profit company to sell transactional email and also email marketing as a service?
Do you mean legally or technically?
Both, I am looking for a solution I can white label and sell as my own service.
Legally, sure. You can use Mail-in-a-Box however you like.
Technically, that’s up to you. The box does what the box does — it’s an SMTP server. Whether you sell people account credentials or give them for free, that’s for you to figure out. But Mail-in-a-Box wasn’t built with that in mind. There may be many new security considerations if the users are your own adversaries. And at high volume you’ll likely get blacklisted by ISPs quickly if you aren’t monitoring things closely, which Mail-in-a-Box isn’t going to be able to help you with.
At pretty much any volume it would almost certainly be cheaper to use any of the transactional email providers out there than to create your own. Mail-in-a-Box is likely a more expensive system for managing email than pretty much any paid service because of the hosting costs and your own time. Trying to save or make money with Mail-in-a-Box probably would be a mistake.
Can I use Mail in a Box as the platform but have users choose their own SMTP service kind of like what Moon Mail does
Mail-in-a-Box is the SMTP service, so, no, choosing an SMTP service is not a feature in Mail-in-a-Box.
Can I create multiple servers for SMTP and have Mail in a Box randomly select which server to use with sending emails.
Again, that is something that MiaB does not support. I do not even think that postfix supports that, but I am not certain on that.
Also, contrary to what Josh posted earlier, you CAN choose a SMTP server to relay mail within postfix. However, that is not supported within the parameters of this project which is likely why Josh responded in the negative. However, if you were to do this it would be considered an ‘unsupported modification’ so nobody around here would be likely to assist with any issues you may encounter, AND the modifications you make would be overwritten constantly by MiaB so you would have to redo your modifications to postfix which usually equates to more trouble than it is worth.
I think im just going to go with elasticemail: https://elasticemail.com/tag/whitelabel/ instead of Mail in a Box. They offer a white label solution. and its pricing is very beneficial to my organization. Thank you for your feedback and support.