I Tested Where My Emails Were Actually Landing: Here’s What an Inbox Placement Check Revealed (and How I Fixed It)

Three campaigns in a row underperformed. No obvious reason. Send times consistent, list unchanged, subject lines arguably better than the ones that used to work fine. So I did the thing I should have done months earlier: stopped guessing from the open rate and ran an email inbox tester to see where these things were actually landing.

An inbox placement check sounds like a small, technical step. It isn’t, really. It’s the difference between assuming there’s a problem and actually watching it happen in front of you.

What the Check Actually Showed

The premise is simple. Send a campaign, then look across a spread of real inboxes to see which folder it lands in, rather than trusting delivery confirmation, which only tells you the email arrived somewhere, not that anyone will see it.

I ran the check across several Gmail accounts kept specifically for this, plus a couple of Outlook addresses for comparison.

Almost every Gmail inbox filed the campaign under Promotions. Not spam. Promotions, arguably the quieter problem, because the email technically “arrived” and will simply sit there, unread, indistinguishable from everything else in that tab.

I’d half-expected spam, if I’m honest. Spam at least points to a known, nameable issue with sender reputation. Promotions is stranger to sit with. Nothing about it says “your domain is in trouble.” It just quietly limits how many people will ever open what you send.

Ruling Things Out

Before assuming anything, I went through it properly. List quality, checked. Sending frequency, unremarkable. Authentication records, all passing. None of the usual culprits explained a pattern this consistent.

That’s when it became clear the email inbox tester wasn’t pointing at reputation at all. It was pointing at categorisation, a separate mechanism entirely, and a much harder one to fix by instinct. Gmail’s model reads formatting, sending behaviour, and content signals to decide whether something reads as promotional. You can pass every trust-based check available and still lose on tone and structure.

You can’t undo months of a domain being read a certain way by tweaking one subject line. I’d tried that logic before running the test. It hadn’t worked, and now I understood why.

Where MailMend Entered the Story

Someone who’d hit the same wall mentioned MailMend a few weeks later, almost in passing. What caught my attention wasn’t a claim or a pitch, it was that the company’s own process starts with something close to the exact inbox placement check I’d already run myself. Seed inboxes, rotated, checked for where campaigns actually land before anything else happens.

From there, MailMend describes moving into what it calls a promotional threshold analysis, reading the same categorisation signals I’d been trying to piece together manually, but doing it as a defined process rather than guesswork. The output, per the company, is a piece of code generated specifically for the Klaviyo account being tested, added into the templates already in use. No changes to subject lines, copy, or design, according to MailMend, and no access to the subscriber list.

Putting It to the Test

Setup took about five minutes, by MailMend’s own account, largely because the code arrives pre-generated from the account’s specific inbox placement check results rather than needing manual configuration on my end. Results are said to show within 24 to 48 hours.

There’s a guarantee sitting behind it too: a minimum 15 per cent revenue increase over a paid seven-day trial, with an extension or full refund on offer if that mark isn’t hit. I can’t independently verify how that plays out across every account that’s a limit worth being upfront about but it’s specific enough as a claim to take seriously rather than wave off as boilerplate.

What to Flag Before Trying This Yourself

An inbox placement check is only as useful as what you do with it, and MailMend’s entire premise rests on the diagnosis being categorisation rather than reputation. If your own check shows mail landing in spam rather than Promotions, this isn’t the right tool, the company says as much itself, and doesn’t currently address spam placement at all. It’s also built specifically for Klaviyo, so anyone on a different platform is out of luck here regardless of what the test reveals.

Pricing isn’t published. It’s custom, demo-based, meaning the real cost only becomes clear once you’re a few steps into the process already.

What I Took From It

Running the email inbox tester changed what I thought the actual problem was, and that mattered more than any fix that came after it. The categorisation issue it uncovered was never going to be solved by cleaner lists or sharper subject lines. Whatever comes next for anyone else running this test, the check itself is the part worth doing first, everything else depends on what it shows.