The hard part of a healthtech signup email isn't calling a send API. It's proving that a dedicated domain is ready for more welcome-email traffic without losing the evidence needed to explain each verification link later. Short answer: use a gradual warmup plan controlled by four signals — auth...
Source: [Dev.to](https://dev.to/marcorossi4891/healthtech-welcome-email-4-api-signals-before-raising-dedicated-domain-volume-1jbe)