PLAYBOOK: Separate transactional and marketing email so one never poisons the other.

PLAYBOOK: Separate transactional and marketing email so one never poisons the other.
A deliverability source told us the single biggest avoidable mistake is sending receipts and promos from the same domain.
— Split sending domains: mail. for marketing, txn. for transactional
— Give each its own DKIM key and its own reputation to protect
— Route password resets and receipts through a dedicated IP that never touches a campaign
— Set distinct DMARC reporting so you can see which stream is degrading
— Never let a promo go out on the transactional stream 'just this once'
The day promos tank your password-reset deliverability is the day support drowns. Watch this.