Email Marketing and Deliverability
Core concepts
Deliverability questions test authentication (SPF, DKIM, DMARC), sender reputation, bounce handling (hard vs. soft), and engagement-based sending. Know that hard bounces (invalid address) should be suppressed, soft bounces (temporary) retried, and that unsubscribe and preference centers must comply with CAN-SPAM/GDPR. Understand A/B testing, send time optimization, and token usage in emails.
Traps
- Confusing hard bounce (permanent, suppress) with soft bounce (temporary, retry).
- Assuming a high send volume alone hurts deliverability - engagement and list hygiene matter more.
- Forgetting that DKIM signs messages and SPF authorizes sending IPs; both are needed alongside DMARC alignment.
- Mixing up operational (transactional) emails, which can bypass unsubscribe, with marketing emails, which cannot.
Rule of thumb
If a question asks how to improve deliverability, the answer is usually segment to engaged audiences, suppress hard bounces, authenticate domains, and honor preferences - not buying a new IP.
Worked example
A client sees rising soft bounces. You confirm addresses are valid (soft = temporary), then implement retry logic and suppress only confirmed hard bounces. Forcing all bounces to suppress would remove reachable contacts.