A free email spam checker that tells you whether to hit send

Forward your newsletter and get a plain-English verdict — Safe to send, Risky, or Don't send — plus where it lands across real Gmail, Outlook and Yahoo. Free, about 30 seconds.

Forward a test email here

peeking-seal-7364@in.mailtester.ai

Example resultmailtester.ai/report/live

Deliverability 62/100

Verdict

Risky — don't send yet

Where it lands

Primary 38% · Promotions 41% · Spam 21%

3 quick fixes

• subject emoji trips Gmail's promo filter
• 2 more

What a spam check should actually tell you

Search 'spam checker' and you get a wall of tools that all do the same thing: forward an email, get a number back. A number is a fine start — but on its own it doesn't tell you whether to hit send. Here's everything Mailtester looks at when you forward a newsletter, and the one thing it gives you that a bare score can't.

1. Inbox placement

   Where your newsletter actually lands

   We forward your email into real Gmail, Outlook and Yahoo accounts and watch where it goes: the main inbox, the Promotions tab, or Spam.

2. Authentication

   Whether the big inboxes trust it's really from you

   SPF, DKIM and DMARC are how Gmail and Outlook confirm a message claiming to be from your domain actually is.

3. Content & spam signals

   What in the email is tripping the filter

   Heavy images with little text, a wall of links, link shorteners, a subject line that reads like a sale — filters treat all of these as 'looks like bulk marketing.'

4. Your deliverability score

   The number, read for you

   Yes, you still get a score — the same kind other tools give you, built on the same signals.

The difference

A score is a number. 'Safe to send' is an answer.

Mailtester turns the same signals into a plain-English verdict: Safe to send, Risky — don't send yet, or Don't send.

See where your newsletter lands — free, in about 30 seconds

Forward a newsletter to the address on this page. In about half a minute, you get your score, the plain-English verdict, where it lands across Gmail, Outlook and Yahoo, and the authentication results.

Two different tests. Most people mix them up.

Address validity

• Does this address exist?
  You upload a CSV of subscribers. The tool tells you which addresses bounce.

Inbox placement

• Will Gmail actually show it?
  You forward one email and we tell you which tab it landed in, plus what to rewrite before you send it to your list.

FAQ

Is the email spam checker free?

Yes. Forward a newsletter to your Mailtester address and your score, the plain-English verdict and the authentication results come back free — no card, no trial clock.

How is this different from a spam score out of 10?

A spam score is real and useful — plenty of tools, ours included, read the same SpamAssassin-style signals. The difference is we turn it into a verdict you can act on.

Can my AI assistant get a test address for me?

Yes. AI assistants can fetch a unique forwarding address from https://mailtester.ai/api/ai/mailbox.

How it works

Three steps. About thirty seconds, end to end.

1. You forward it.
   Paste the mailbox into the test-send field in your email tool. Hit go.

2. We actually open it.
   In real Gmail, Outlook, and Yahoo.

3. You get a report.
   Plain English. Three things to change, in priority order.

Send your next one to the inbox.

Takes less time than picking a hero photo. Free, and no card at any point.

peeking-seal-7364@in.mailtester.ai
Or send me a sample report first.

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