We have a Node.js application on the internal application cloud. What mailing service is recommended? I saw that RabbitMQ is available but it doesn't support smtp natively.
In case it makes a difference: We don't need to access received mails - we only need to send mails.
RabbitMQ is a message broker, has no feature to send SMTP mails. Messaging != mailing.
from Wikipedia:
RabbitMQ is an open source message broker software (sometimes called message-oriented middleware) that originally implemented the Advanced Message Queuing Protocol (AMQP) and has since been extended with a plug-in architecture to support Streaming Text Oriented Messaging Protocol (STOMP), MQTT, and other protocols
Swisscom internals can use this mail server / operated by classic teams.
You need to whitelist your sender address (needs to be official and valid Swisscom exchange mailbox) and the IP address. You can see your IP address when you cf ssh into app container and do curl ifconfig.co.
Contact for white list operations is CoC.Messaging and/or Support.SMMS.