Inbox placement is the single most invisible part of email marketing. You do not see it on a dashboard. You feel it in the slow erosion of campaign performance, the open rate that keeps dropping for no obvious reason, and the support tickets from people asking why they have not heard from you in weeks. If you fix deliverability, every other lever in your program gets stronger.
01. Whitelist after purchase.
If your emails keep ending up in spam, it is often because subscribers have not actively signaled to their inbox provider that they want to receive your mail. The single best moment to ask for that signal is right after a customer makes their first purchase.
The first post purchase email is opened more than almost any other email you will ever send. Use that real estate. Ask the customer to add your sending address to their contacts so future emails route directly to the inbox. It is a small ask in the moment they are most willing to say yes.
02. Clean up your list.
Clean your list regularly. When you send a campaign, mailbox providers check the ratio of inactive emails to active ones. Too many inactive addresses on a single send is the single fastest way to get flagged. Your list quality is not a vanity number. It is a deliverability input.
Suppress unengaged subscribers monthly. Remove hard bounces immediately. Ignore the temptation to keep a bloated list for the optics. A list of 8,000 engaged subscribers will outperform a list of 30,000 mostly dead ones every time.
03. In depth segmentation.
Sending the same email to your entire list is a deliverability red flag in addition to being a relevance red flag. With the iOS update, you can no longer cleanly identify who opened your email, but that does not change the underlying mechanic. Mailbox providers reward sends that go to a relevant audience and penalize sends that go to everyone.
Target the right segment with the right subject line. Send your highest performing campaign to the segment most likely to engage. Sender reputation compounds upward.
04. Stop using promotional subject lines.
If your subject line is built around words like free, discount, sale, limited time, or any variation of the same, it is going to land in the promotional tab at best and the spam folder at worst. The filters are not subtle. They were tuned years ago and they are still doing their job.
Write subject lines that signal a real conversation, a real insight, or a real moment. Save the promo words for the body where filters do not weight them as heavily.
05. Build a real relationship.
If your subscribers do not remember signing up, or if every email feels like a sales pitch, they will eventually mark you as spam. Past a certain volume of complaints, your sends will route to the junk folder no matter what you send.
The fix is upstream of any individual campaign. Start the relationship with value, education, and tone before you ask for the sale. Subscribers who feel like they know the brand do not mark its emails as spam, even when they are not interested in a given offer.
Deliverability is a relationship, not a setting.
SPF, DKIM, and DMARC matter. So does the warm up. So does the IP. But the biggest deliverability lever is how the audience feels about your sends. Maintain that and the technical stuff stays uneventful.
Five disciplines that keep you in the inbox.
- Ask customers to whitelist your address inside the first post purchase email.
- Suppress unengaged subscribers monthly to keep the active to inactive ratio healthy.
- Segment every send. Mailbox providers reward relevant sends and penalize whole list blasts.
- Avoid promotional words in subject lines. Save them for the body copy where they weigh less.
- Start the subscriber relationship with value, not a discount. Complaints, not opens, are what kill deliverability long term.