Scout Report: SaaS Transactional & Marketing Email Deliverability Architecture

Stacklist should architect `mail.stacklist.com` on Loops' shared SES pool, using a single dedicated subdomain for all product email and configuring a custom Return-Path subdomain for DMARC alignment. This strategy, combined with relaxed DMARC alignment and a 4-week warming period using only transactional mail, is crucial for maximizing inbox placement at low volume and meeting 2024+ Google/Yahoo sender requirements.