The SaaS product email stack
Instant transactional mail, plus lifecycle email that knows your product.
For a SaaS product, some email is not marketing — it is part of the product. A password reset or an invite that arrives late, or lands in spam, is a broken feature. That mail needs a transactional API with its own reputation, ideally on its own subdomain: Postmark for reliability and clear logs, or Resend if your team wants a developer-first experience.
Lifecycle email is different work. Onboarding sequences, feature nudges and re-engagement should be driven by what people actually do in your product, which means a tool that ingests product events. Customer.io is built for exactly this; Loops is a lighter, faster-to-adopt alternative for smaller teams.
Support conversations belong in a shared inbox — Help Scout or Front — kept separate from both transactional and lifecycle sending. And because a SaaS domain is a prime spoofing target, watch your DMARC reports through dmarcian or Valimail so you reach and hold p=reject safely.
The separation that matters: product-critical mail on its own subdomain and reputation, behavioural email driven by real product data, and support kept in its own lane.