Short answer: for a healthtech marketplace seller alert, choose an email API with custom-domain DKIM, a pre-send suppression check, and an event list that a scheduled job can poll. Keep the notification outside the order transaction. This design fits a standard US/EU SaaS workflow when delayed ...
Source: [Dev.to](https://dev.to/kaelvyn47/nodejs-welcome-flow-explained-custom-domain-email-api-suppression-dkim-polling-24pk)