STAMPWING / MULTI-PROJECT TRANSACTIONAL EMAIL CHECKLIST
Last reviewed: October 4, 2026

Inventory (one row per app and environment)
[ ] Application owner and operational contact
[ ] Visible From domain; signing domain; envelope/return-path domain
[ ] Provider account/project and region
[ ] Separate Test and Live credentials; secret storage and rotation owner
[ ] Domain verification and preserved mailbox MX records
[ ] Password reset, verification, receipt, and notification event owners
[ ] Template IDs and immutable version references
[ ] Stable business-event ID and idempotency key policy
[ ] Durable outbox and recovery process for uncertain submissions
[ ] Signed webhook endpoint; durable inbox; duplicate/reordering tests
[ ] Bounce and complaint handling; project and provider suppression scope
[ ] Daily/monthly limits, alerts, retention, and spend cap
[ ] Evidence for queued, provider-submitted, and receiving-server-accepted states
[ ] Test fixtures are visibly simulated; no customer addresses in CI
[ ] Controlled delivery check before Live; authentication alone is not inbox proof
[ ] Runbook for rotating credentials, pausing sends, and recovering incidents

Example inventory headings (no credentials):
App | Environment | From domain | Key reference | Webhook endpoint | Limit | Owner

Project separation organizes access and diagnosis. Shared infrastructure can
still share reputation and provider limits; do not assume complete isolation.