Blacklist Check Came Back Clean, But Emails Still Land in Promotions? Here’s What’s Actually Happening (MailMend Review)

It started with a complaint from one of our own newsletter contributors: open rates had dropped, and nobody on the team could work out why. The sending domain looked fine. Nothing in the content had changed. So the first instinct was to run an email blacklist check.

That felt like the obvious starting point. A blacklist listing explains a lot in one go, poor sender reputation, spam folder placement, the works. We ran the check through a couple of standard tools, expecting an answer straight away.

Nothing came up. The domain was clean. No blocklists, no flagged IPs, no warnings of any kind.

What We Initially Thought

Our assumption was that an email blacklist check would tell us more or less everything worth knowing about deliverability. If the domain wasn’t blacklisted, surely the mail was reaching the inbox as intended.

That assumption didn’t hold. A clean email blacklist check confirms sender reputation isn’t actively damaged, it says nothing about where an email lands once it arrives. Two separate questions, easily mistaken for one.

What We Tried or Looked At

Before digging further, we went through the standard checklist: authentication records, sending frequency, list hygiene, subject line testing. All reasonable advice, and none of it explained the pattern we kept seeing, which was mail consistently arriving in the Promotions tab in Gmail rather than the main inbox.

An email blacklist check, run again to rule out anything intermittent, came back clean a second time. That was the moment it became obvious this wasn’t a reputation problem at all. It was a categorisation problem.

The Point Where We Started Looking Differently

Gmail sorts incoming mail using its own set of signals, formatting patterns, sending behaviour, and other markers that have nothing to do with blacklist status. Mail can pass every reputation test available and still get filed under Promotions, simply because it reads, structurally, like promotional mail.

That reframed the whole investigation. This wasn’t a deliverability failure in the conventional sense. It was a tab problem, and an email blacklist check was never built to catch it.

Finding MailMend

MailMend came up in a wider conversation about tools built around Klaviyo. According to its own materials, the company focuses specifically on this categorisation gap rather than the reputation side an email blacklist check is designed for. Its approach works within the Klaviyo account itself, a piece of code generated per account, without altering subject lines, copy, or design.

What We Found

MailMend describes inbox placement as depending on a combined set of signals it calls a “promotional threshold.” The company states it first tests where a brand’s mail is currently landing, analyses those signals through its own process, then builds account-specific code intended to shift placement from Promotions to Primary. Setup, per MailMend, takes around five minutes, and results are said to show within 24 to 48 hours.

MailMend also references a revenue guarantee: a minimum 15 per cent increase during a paid seven-day trial, with an extended trial or full refund if that isn’t met. Customers cited publicly include Dr Squatch, StickerYou, and Clevr Blends. None of this alters what an email blacklist check covers, it simply sits on a different layer of the same underlying problem.

What Stood Out and What to Consider

What stood out was the framing: MailMend positions itself as filling a gap left by standard deliverability practice, an email blacklist check included, rather than replacing it. That’s a fair distinction, provided the mechanics behind it hold up under scrutiny.

A few things are worth weighing before treating this as settled. The tool is built specifically for Klaviyo, so brands running other platforms would need a different route entirely. Pricing is custom and demo-based rather than published, which some readers will find less transparent than they’d like. The company also notes it doesn’t currently address spam-related issues, which is a separate and arguably more serious problem than tab placement. And the 15 per cent guarantee, however specific-sounding, is a claim we haven’t independently verified through case study data of our own.

What We Took Away

Running an email blacklist check still matters. It rules out a real and fairly common cause of poor performance. Our research suggests, though, that it isn’t the whole picture for brands whose mail is technically undamaged yet still underperforming.

The more useful question isn’t only whether an email blacklist check comes back clean. It’s whether the mail was ever routed toward the primary inbox to begin with. Those are different problems, and treating them as one costs us more time than it should have.