A pattern we see every few months: a shop owner sends the same weekly newsletter they've sent for two years, and open rates fall by half in a month. Nothing changed in the email. What changed is where it landed. Email deliverability is the share of your sends that reach the inbox instead of spam, and three things decide it: whether your domain is authenticated, how recipients react to your mail, and how clean your list is. All three are fixable this week, mostly inside Klaviyo or Mailchimp settings you already have.
Delivery means the receiving server accepted your message. Deliverability means it reached the inbox. A campaign can show 99% delivered while most of it sits in spam or Promotions, because Gmail, Yahoo, and Outlook accept the mail first and decide placement second. Your delivery rate hides the problem. Opens, clicks, and spam complaints reveal it.
That gap is why so many owners find out late. The dashboard says delivered, so the first clue is usually a quiet sales week after a send that normally brings in orders. If revenue per campaign drops while list size holds steady, check placement before you rewrite a single subject line.
Most small business emails land in spam for one of four reasons: the sending domain isn't authenticated, too many recipients mark the mail as spam, the list holds old or purchased addresses, or volume jumped suddenly. Copy and design matter far less than people assume. Mailbox providers judge the sender first and the message second.
Google publishes the numbers it judges senders by. Its email sender guidelines FAQ tells senders to keep spam rates below 0.1% and never let them reach 0.3%. That's three complaints per thousand emails. A 2,000 person list can cross the line with six annoyed subscribers, which is why a single badly targeted blast can hurt for weeks.
The same guidelines define a bulk sender as anyone sending close to 5,000 messages a day to personal Gmail accounts, and require those senders to authenticate with both SPF and DKIM, publish a DMARC record, and offer one-click unsubscribe on marketing messages. You might be nowhere near 5,000 a day. Meet the bulk standard anyway. It's the clearest written description of what a trustworthy sender looks like, and Yahoo's sender best practices ask for nearly the same things.
You set up all three as DNS records at your domain registrar, using values your email platform gives you. SPF lists who may send for your domain, DKIM signs each message, and DMARC tells mailbox providers what to do when a message fails both. In Klaviyo or Mailchimp, plan on about thirty minutes of work plus a day for DNS to update.
The step most small businesses skip is sending from their own domain at all. If your campaigns go out through a shared platform domain, or from a free Gmail or Yahoo address, you're borrowing someone else's reputation and failing alignment checks. In Klaviyo this setting is called a branded sending domain. In Mailchimp it's domain authentication. Turn it on, then add a DMARC record starting with a policy of none so you can read the reports before you enforce anything.
One caution from experience: check for an existing SPF record before adding a new one. A domain can only have one, and we regularly find two (one from Google Workspace, one pasted in later from an email tool), which quietly breaks both.
A clean list contains only people who asked to hear from you and have opened or clicked something recently. That means no purchased contacts, no addresses scraped from business cards without permission, and a sunset rule that stops mailing people who've ignored you for months. Smaller and engaged beats bigger and silent, every time.
We're opinionated on this one. Most owners treat list size as the score, so they resist removing anyone. But mailbox providers watch engagement, and sending to thousands of people who never open teaches Gmail that your mail isn't wanted. That lesson then applies to your good subscribers too.
A sunset rule that works for most small lists: build a segment of people who've received at least ten emails and haven't opened or clicked in 120 days. Send them one plain re-permission email asking if they still want to hear from you. Suppress everyone who doesn't respond. Expect the list to shrink and revenue per send to hold or improve, since those contacts weren't buying anyway. It's the same logic behind our piece on why growing website traffic doesn't always grow sales: volume that doesn't engage isn't an asset.
Work through this in order. The early items fix the largest share of problems, and the later ones keep the fix from wearing off.
Expect two to six weeks of consistent, well-targeted sending before inbox placement recovers, and longer if spam rates stayed high for months. Authentication fixes register within days. Reputation rebuilds slowly, because mailbox providers want sustained evidence that recipients open, click, and don't complain. Nothing speeds this up except good sending.
During recovery, mail only people who engaged in the last 30 to 60 days, keep your schedule steady, and watch the spam rate in Postmaster Tools after each send. Don't switch platforms hoping for a fresh start. Your domain carries its reputation with it, and a sudden move to new sending infrastructure looks suspicious on its own.
Deliverability also changes how you should read your other numbers. If you're deciding how to allocate marketing budget across channels, an email program that looks weak may only be hidden in spam folders. Fix placement before you cut the channel. And if you're leaning on automation to produce more campaigns, our guide to using AI in content production without losing brand voice covers how to keep that extra volume worth opening.
For Bay Area shops and service businesses heading into the holiday season, the timing matters. November is when inboxes are most crowded and filters are least forgiving, so October is the month to do this work. If you'd rather hand it off, our email marketing services for Klaviyo and Mailchimp include authentication and list cleanup as part of setup.
Start today with the smallest step: send your latest campaign to a personal Gmail account, choose Show original, and see whether SPF, DKIM, and DMARC all say PASS. It takes two minutes and tells you which half of this checklist to tackle first.
.png)
