05/01/2026
Every week I get the same question:
"Why are my emails going to spam?"
And almost every time, the sender wants to talk about subject lines. Spam words. Emojis. Whether "Hi {first_name}" still works.
That's not where the problem is.
Deliverability is decided long before the inbox sees your subject line. It's decided by:
→ Domain age and authentication (SPF, DKIM, DMARC — all aligned, not just present)
→ Whether your transactional and marketing streams share an IP (they shouldn't)
→ How you warmed up — or didn't — when you started
→ Your complaint rate over the last 30 days
→ Whether your list hygiene is a discipline or an afterthought
Mailbox providers don't read your copy. They read your reputation.
Fix the architecture first. Then worry about the words.
What's the deliverability mistake you see most often?
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