Return-Path
The envelope sender address used for bounces and SPF alignment.
Return-Path is the address that receives bounces and is checked for SPF. It can differ from the visible From address. For DMARC to pass via SPF, the Return-Path domain must align with the From domain.
reading this as SaaS product teams
A SaaS product sends on behalf of its customers, so the deciding factors are tenant isolation, whether suppressions can be scoped rather than global, and whether support can answer why one specific account did not receive one specific email. Lifecycle automation and transactional sending usually need to coexist.
Applied to return-path, that means weighing multi-tenant support, event stream, the suppressions API, and operating track record ahead of the rest, against trial expiry notices, dunning, onboarding sequences, and per-tenant transactional mail.