Creative only wins on mail that lands. Check spam placement and reputation first.
Placement is the first variable in your email program. Creative is the last. You think the copy is tired, so you spend a month on subject lines, art direction and a new template. Revenue doesn't move, because much of your file stopped receiving your mail eighteen months ago, and no dashboard in your account reports it.
Promotions is fine: it's where Gmail files marketing mail and where shoppers go looking for it. Spam is where mail goes to die. Spam placement creeps in slowly, and monthly totals absorb it.
One home-goods brand shows where that ends. It kept mailing everyone, including 204,000 inactive purchasers. Engagement per send fell. Mailbox providers trusted each send less, so fewer people saw the next one.
No creative decision caused that slide, and none would have fixed it. AI made creative cheap, which strengthens the case for putting it last.
Since February 2024, Gmail and Yahoo require bulk senders to authenticate with SPF, DKIM and DMARC, to offer one-click unsubscribe and honor it within two days, and to keep user-reported spam under 0.3%. Aim for under 0.1%. Microsoft applied the same authentication requirement to Outlook.com in May 2025. Klaviyo adds the one-click header for you; check every other system that sends as your domain.
Then set up Google Postmaster Tools for your sending domain and read it every week. It's Gmail's own count of how often your subscribers mark you as spam.
Since September 2021, Apple Mail can load your images whether or not anyone opens the email, so open rates overstate engagement. Judge engagement on clicks, site visits and orders. A program can report a steady open rate while Gmail files a growing share of it as spam. Read click rate by mailbox provider, and read Postmaster Tools.
Seeds show you what a stranger receives: whether every flow arrives, how it renders, and whether anything lands in spam. They can't show you how Gmail treats your engaged subscribers, because Gmail filters each inbox on that person's history. Use seeds for the plumbing and Postmaster Tools for the reputation.
Send marketing from a branded subdomain, authenticated and aligned to your From domain. Where your platforms allow it, put transactional mail on a subdomain of its own. The split limits the damage a bad promotional month does to your shipping confirmations, without walling it off.
Before DMARC moves past p=none, list and authenticate every system that sends as your domain: Shopify notifications, the helpdesk, the subscription app, the review app. A stricter policy tells mailbox providers to junk or refuse mail that fails. Any sender you missed stops arriving the day you tighten it.
Define engagement without Apple's machine opens: a click, a site visit or an order, or an open your platform can confirm came from a person. Klaviyo can separate Apple privacy opens; exclude them. No engagement in 90 days drops a profile to reduced campaign cadence; 180 days triggers one last-chance message; 240 days suppresses them.
Excluding people from campaigns doesn't change your Klaviyo bill; suppressing them does, and a suppressed profile gets no flows either. Put "fewer emails" beside "unsubscribe" on your preference page, so a subscriber who wants less mail has a choice short of leaving.
Smart Sending skips anyone you messaged in the last 16 hours (24 for SMS) by default. It filters on recency, so the people it drops are recent recipients, and those are disproportionately customers inside abandonment and post-purchase flows. Reconcile every campaign: segment size against actual recipients. A gap that widens each month means your cadence is too high and the setting is hiding it.
In the US, CAN-SPAM lets you email customers who never opted in, as long as the mail is honest, carries your postal address and a working unsubscribe, and you honor opt-outs within ten business days. Your email platform's rules and Gmail's filters are stricter than the law, so design for opt-in anyway.
Ask for email and SMS consent separately, each with its own disclosure beside it. Never tick a box for the customer. Addresses added without a clear yes draw complaints, and complaint rate sets your placement for everyone.
Fix deliverability before peak. If it breaks during peak, cut sends to your engaged file and fix authentication the same day. Leave the rebuild for January. A November deliverability failure costs you the biggest cohort you'll acquire all year. The cost stays hidden until their second orders fail to arrive, which is why the fix comes first.
Reputation is earned in the quiet months and spent in November.
This is one chapter of The Second Order, which is free and readable in full on a single page with no form in front of it.