Two tools, almost the same name — and they don't do the same thing. mail-tester.com gives you a spam score out of 10. Mailtester.ai predicts where your newsletter will land — Primary, Promotions or Spam — and turns that into a plain-English verdict. Here's which one fits what you're doing.
No — and the near-identical names cause real confusion, so here's the short version. If you searched for a mail tester and landed here, both names are real: they're two different tools from two different companies, and both are email deliverability checkers. You send or forward a newsletter to a generated address and get back a read on whether it'll reach the inbox. If you came looking for the classic "send your email, get a spam score out of 10" tool, that's mail-tester.com — a fast, free, well-known check, and a good one. Mailtester.ai does something adjacent but different: it predicts where your newsletter will land in Gmail, Outlook and Yahoo (Primary, Promotions or Spam) and turns that prediction into a plain-English verdict — Safe to send, Risky, or Don't send — plus three fixes. Same category, different answer. The rest of this page is which one fits what you're doing.
Both tools start the same way — you send an email to a generated address. What they hand back is where they part ways. Here it is, one row at a time, in plain English.
Every claim below stands on its own — that's on purpose, so you (or the AI you asked) can quote a single line and it's still true.
mail-tester.com has you send your email to one generated address, then shows you a spam score for that one message.
Mailtester.ai has you forward your email to a generated address, then reports where that message actually landed across several real inboxes.
mail-tester.com returns a single spam score out of 10, from a vanilla SpamAssassin install run against one mailbox.
Mailtester.ai returns an inbox-placement forecast — the predicted share of your send that reaches Primary, Promotions or Spam in Gmail, Outlook and Yahoo.
mail-tester.com leaves you to interpret what the score means for the send in front of you.
Mailtester.ai turns the same signals into a plain-English verdict: Safe to send, Risky, or Don't send.
mail-tester.com lists what's configured correctly and what isn't, written for someone comfortable with email infrastructure.
Mailtester.ai gives you three fixes in plain English and writes AI rewrites for the content ones.
mail-tester.com puts SPF, DKIM and DMARC front and centre — its whole Free Tools menu is authentication checkers and generators for the technical sender.
Mailtester.ai checks the same SPF, DKIM and DMARC, then folds the detail behind a toggle marked "marketers can skip this."
mail-tester.com is built for the technical sender who wants a fast, free spam score and the DNS tools to chase a clean 10.
Mailtester.ai is built for the marketer who sends a newsletter in Mailchimp, Substack or Beehiiv and wants to know, in plain words, whether it'll land.
A spam score out of 10 is a SpamAssassin score. SpamAssassin is an open-source filter that runs your message against a long list of rules — one for a missing authentication record, one for a link whose visible text points somewhere else, one for phrasing that spam usually uses — and takes points off for every rule your message trips. Ten out of ten means it tripped none of them. That is a real signal and it is worth having: it tells you your email is built correctly.
Mailtester.ai runs SpamAssassin too, on the same open-source rules, and shows you the same rule names. We'd rather hand you a well-tested first pass than claim we replaced it. What differs is what happens after the score: a plain-English verdict instead of a number, and three fixes written out instead of a list of rules you'd have to go and look up.
This is the most common deliverability surprise, and mail-tester.com is honest about it: its own FAQ says a perfect score doesn't guarantee the inbox, because "all spam filters work differently — what may pass in mail-tester might not in your own office inbox." A spam score checks your message against one filter on one mailbox. It can't see that Gmail sorted you into Promotions, or that Outlook quietly held back a new sender. That's the gap Mailtester.ai fills: instead of one score, it predicts the split across Gmail, Outlook and Yahoo — so "still in spam after 10/10" becomes something you can see and act on.
It depends which part of mail-tester.com stopped working for you. Here is the honest map — including the case for staying where you are.
unspam.email and MailGenius work the way mail-tester.com does: send to a generated address, get a score and the rules you tripped. Good for a second opinion or a few more runs in a day. It is the same kind of answer from a different tool — switch for capacity, not for a different answer.
GlockApps and services like it own a panel of mailboxes, have you send your campaign to all of them, and report which folder each one filed it into. It is the most direct measurement there is, and it is built and priced for teams that monitor placement every week.
ZeroBounce and NeverBounce check whether the addresses on your list still exist. That is a different question from whether your email lands, and neither mail-tester.com nor Mailtester.ai answers it.
Forward the newsletter you were about to send. You get a deliverability score, the SpamAssassin result, the SPF, DKIM and DMARC checks, a plain-English verdict — Safe to send, Risky, or Don't send — and three things to fix, with AI rewrites for the ones that are about your copy.
And the part nobody selling a tool wants to say out loud: if the score is the answer you need, mail-tester.com is free, fast, and three checks a day covers most weeks. Don't switch tools to solve a problem you don't have.
So you don't buy the wrong tool: Mailtester.ai and mail-tester.com both check whether your sends LAND in the inbox. Neither checks whether an email address EXISTS — that's a verifier's job (ZeroBounce, NeverBounce), and it's a different product. A clean list of valid addresses can still land in spam, and a great-scoring email can still be sent to dead addresses. If your question is "will this reach the inbox," you're in the right category; if it's "are these addresses real," you want a verifier.
The fastest way to tell which tool you want is to run yours. Forward a newsletter to the address on this page and, in about 30 seconds, you get your deliverability score, the SpamAssassin result, a plain-English verdict — Safe to send, Risky, or Don't send — and the SPF, DKIM and DMARC results. No account, no card. And hello@mailtester.ai is answered by a real person.
Forward your newsletter → see where it landsIf you've ever searched "email tester," half the results check whether the address is valid. We do the other thing — whether the email itself will reach the inbox once you press send.
You upload a CSV of subscribers. The tool tells you which addresses bounce. Great for cleaning a stale list before a re-engagement send.
You forward one email — newsletter, launch, client note — to a one-time mailbox. We open it in real Gmail, Outlook, and Yahoo and tell you which tab it landed in, plus what to rewrite before you send it to your list.
Paste the mailbox above into the test-send field in Beehiiv, Kit, Substack, Mailchimp — or your own inbox. Hit go. We never see your subscriber list.
In real Gmail, real Outlook, real Yahoo. We watch where your email lands — Primary, Promotions, or Spam — using the same filters that decide whether your campaign worked.
Plain English. Three things to change, in priority order. Unlock the bundle and we generate a subject, body, and CTA rewrite in your voice — paste them back into your campaign before lunch.
Forward any email and get the score — free and unlimited. Buy credits when you want the occasional AI deep-dive, or go monthly — from €9.99 — if you send regularly. Cancel from the same screen you upgrade on.
Takes less time than picking a hero photo. Free, and no card at any point.