Infrastructure Considerations

Creative and segmentation get most of the attention — but sending infrastructure determines whether your campaigns can scale, survive a DNS change, and recover when something breaks. This video covers the structural layer: IPs, domains and subdomains, ESP configuration, and operational choices that affect deliverability troubleshooting.

Infrastructure decisions made early (shared pool vs dedicated IP, marketing on root domain vs subdomain) are expensive to unwind later. Getting the architecture right lets you isolate problems instead of guessing.

Domains and subdomains for sending

Many brands send marketing from a subdomain (e.g. mail.brand.com) to protect the root domain’s reputation and simplify DMARC. Transactional mail may live on a separate subdomain or stream with its own authentication records.

Alignment matters more than the aesthetic of your From address — the signing domain, return-path, and visible From must cooperate for DMARC and provider trust.

Shared IP pools vs dedicated IPs

Shared pools are fine at moderate volume with good hygiene — you inherit neighbor behavior. Dedicated IPs give isolation but require warming, consistent volume, and ongoing monitoring.

Switching IPs without fixing domain reputation or list quality rarely solves placement problems. Infrastructure changes should pair with authentication audits and engagement discipline.

ESP configuration and operational hygiene

• Document every sending stream: marketing, transactional, sales, integrations.
• Keep DNS change logs — SPF flattening and new ESP includes break easily.
• Use separate API keys and sending domains for staging vs production where possible.
• Plan failover for transactional mail before Black Friday, not during an outage.

When to revisit infrastructure

Major triggers: ESP migration, large list acquisition, crossing high-volume thresholds, repeated Gmail/Yahoo throttling, or adding new channels (SMS provider, direct mail) that share customer identity data. Each event is a chance to re-audit DNS, streams, and monitoring — not just flip a switch.

Learn more: Platform migration services, and Deliverability Recovery program.