I spent 30 minutes on a Friday afternoon trying to figure out why a client's emails kept landing in the Promotions tab.

Same template. Same content. Same list. But a completely different sender was getting Primary inbox placement on the exact same campaigns and I couldn't figure out why.

So I started pulling things apart.

Changed the images. Still Promotions. Stripped out the links. Still Promotions. Swapped to their plain text template. Still Promotions.

Then I changed one thing. The sender email.

Primary. Every single time.

Here’s what we found about how to land in Gmail’s Primary tab and getting out of the dreaded Promotions tab

Inside Klaviyo there are two places a sender email can live.

There's the email address you set up inside your individual flow or campaign. And there's the default sender email sitting inside your organization settings — the one most brands set up on day one and never think about again.

Here's what we noticed across nearly a dozen accounts.

When the sender email in the campaign matches the default email in the Klaviyo organization settings, the email lands in Primary.

When it doesn't match — when someone gets clever with the sender name, uses a different address, or sets up a variation for a specific campaign — Gmail reads that inconsistency and routes it straight to Promotions.

We tested this with one of our clients, Slumber, in real time. Same email sent twice. One from their standard support address that matches their Klaviyo account settings. One from a variation. The screenshots tell the story better than anything I could write.

Primary versus Promotions. Identical email. Barely 1 minute apart. One variable.

Most brands know that landing in Promotions isn't ideal. But here's the part most people underestimate.

Emails that land in the Promotions tab don't trigger push notifications on mobile.

When your email hits Primary, the subscriber's phone buzzes. They see it. They decide in that moment whether to open it or not.

When it hits Promotions, nothing happens. They only see it if they open their email app and actively navigate to the Promotions tab. Which most people don't do on any kind of regular basis.

The open rate difference isn't a rounding error.

Look at what happened across three campaigns for one of our clients before and after we fixed the sender email.

Before: 0.47% placed order rate across three campaigns.

After: 0.78% placed order rate across the next three campaigns.

Same audience. Same offer. Same send frequency.

The only thing that changed was where the email landed.

That's a 66% increase in placed order rate from fixing one field inside Klaviyo settings.

Go into your Klaviyo account. Navigate to Settings, then Organization. Find the default sender email address listed there.

Now go look at your last five campaigns. What sender email did those go out from?

If they match, you're fine. If they don't, you've just found the reason your open rates are softer than they should be and your emails aren't hitting the inbox the way they used to.

This takes about four minutes to audit. It's the fastest deliverability fix most brands will ever make.

The sender email is the one we stumbled on and the one that had the most dramatic and consistent impact across the accounts we tested it on.

But it's not the only thing sending you to Promotions.

There are a handful of other factors, some technical, some content-related, some behavioral, that Gmail weighs when deciding where your email lands. We've been documenting all of them and put everything we know into one place.

It's called Gmail Primary Tab Secrets and you can get it free below.

GET THE GMAIL PRIMARY TAB SECRETS GUIDE

No fluff. Just every lever we've found that influences Primary placement, explained simply enough that you can audit your own account this week.

Reply with the word PRIMARY and I'll personally take a look at your current sender setup and tell you if there's anything else I'd fix first.

— Anthony

P.S. We've now tested this across nearly a dozen accounts with the same result. The sender email match is real, it's consistent, and it's almost certainly affecting brands who have no idea it's happening. Check your settings before your next send.