If I use Starkit do I still need an email provider (i.e. Gmail) or my own mail server (Microsoft Exchange)?
No, if you use Starkit you don’t need an email provider (i.e. gmail or outlook or yahoo) or your own mail server (i.e. Microsoft Exchange). Your Starkit appliance will be your mail server, that means the provider of your email service is you. Of course you can keep and collect your existing email addresses to your own Starkit appliance using the mail collector feature.