Every editorial team has a folder of “we’ll get to this eventually” story ideas. Ours had a note sitting in it for months: why does everyone keep asking about the same Klaviyo tool? It kept surfacing in reader emails, in passing mentions on forums, in a Slack thread from a marketer friend who wouldn’t stop talking about her open rates. Eventually curiosity won out.
The tool was MailMend. The category, broadly, is what people now call an email deliverability platform, though as we quickly learned, that phrase covers a lot of very different things depending on who’s using it.
A Crowded Word
Ask around and “deliverability” means something slightly different to everyone. To some, it’s spam filter avoidance. To others, list hygiene. To a growing number of Klaviyo users, apparently, it means one specific thing: whether Gmail decides an email belongs in Primary or gets shuffled off to Promotions, unread and unloved.
That last definition is the one MailMend has built its entire pitch around, and it’s narrower than most of what gets marketed under the same banner.
The Mechanism, As Explained to Us
Rather than adjusting subject lines or redesigning templates from the usual advice, MailMend’s method sits at the header level. A snippet of code, generated individually for each Klaviyo account, gets embedded into the templates already in use. Nothing about the copy changes. Nothing about the design changes. The company is specific about this: existing authentication protocols (SPF, DKIM, DMARC) stay untouched, and no subscriber data is accessed or stored in the process.
If that’s accurate, it separates MailMend from a fair chunk of the email deliverability platform category, where “optimisation” often means rewriting or restructuring the email itself.
Three Steps, Five Minutes
MailMend’s own account of the process is refreshingly compact. Seed inboxes are used to establish where a brand’s current campaigns are actually landing. From there, the company runs what it calls a promotional threshold analysis, reading the combined signals inbox providers use to sort mail. The output is a piece of account-specific code, and the whole thing is said to take about five minutes to implement.
Results, according to MailMend, show up within a day or two. 24 to 48 hours is the figure the company gives with average gains cited at 50 to 100 per cent across opens and clicks. Big numbers. Numbers that invite a raised eyebrow, frankly, until you look at what sits behind them.
The Guarantee Is Where It Gets Interesting
Plenty of platforms in this space lead with a free trial and leave it there. MailMend goes a step further: a minimum 15 per cent revenue increase, tested over a paid seven-day trial. Miss that mark and the company says it will either extend the trial at no cost or issue a full refund.
That’s a genuinely uncommon structure for the category. Most tools ask for trust upfront and hope the numbers work out. This one ties its own pricing to a measurable outcome, which shifts some of the risk back onto MailMend rather than the brand testing it.
Named Names
Dr Squatch, StickerYou, and Clevr Blends all appear as customers in MailMend’s own case material, with reported increases ranging roughly from 20 to 50 per cent depending on the account. We haven’t independently audited these figures, worth saying plainly but they’re specific enough, and consistent enough with the company’s broader claims, to be worth noting rather than dismissing.
Where the Cracks Show
No review is complete without the awkward questions. MailMend doesn’t publish the actual mechanics of its header code, which is a reasonable commercial decision but leaves the central claim, “we change nothing, yet everything improves” resting largely on trust. Pricing is custom and demo-led rather than listed anywhere, which won’t suit brands who prefer to compare costs before a sales conversation. And by the company’s own admission, MailMend doesn’t touch spam placement at all. If a brand’s real problem is spam folder burial rather than a Promotions tab issue, this isn’t the fix.
It’s also Klaviyo-only. Brands on other platforms can stop reading here.
Where That Leaves Things
MailMend isn’t attempting to be everything the term email deliverability platform could mean. It’s solving one problem, precisely defined, and appears to know exactly what it isn’t trying to do which, oddly, is one of the more reassuring things about it.
Whether that’s the right fit comes down to a fairly blunt question: is Promotions-tab placement actually the issue, or is something else going on further upstream? Get that wrong, and no platform in this category that MailMend included will move the needle much.
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