amazee.io enables you to send out emails from any environment. There is a local MTA in place which takes care of that. However if you need high reliability in sending emails out you should consider using a third party mail provider.
If you plan on using an external Mail Provider you can make use of the Drupal SMTP Authentication Module.
We support the possibility to reroute emails which are sent from Drupal. You can enable this setting for every site you host on amazee.io
We list our outgoing mail servers in an SPF Entry. If you send emails via amazee.io we suggest adding this record to your DNS.
example.com. IN TXT "v=spf1 a mx include:spf.amazee.io ?all"