Email DeliverabilityEmail Deliverability Test : How To Do It Right to Skyrocket your Deliverability in 2025Doing an email deliverability test is a great practice to avoid spam filters and improve your inbox rate. In this article, we cover how to properly do it.
Just before you go further in this article, we’re thrilled to announce that after months of development and fine tuning, we have finally released our free email spam test.
It has been developed and optimized with much love and passion to give you the most reliable spam score and deliverability check.
This deliverability test, combined to our email warm up service, offers a very effective and global cold email deliverability solution.
Because, yes, as you’ll understand it by reading this article, most deliverability tests are biased and not reliable today.
Good reading.
We’ve seen so many times people run deliverability tests and wonder why their results are so different than the reality of their campaign statistics.
Why? Because most people are not aware that their sending tool alone can make them land in spam.
It’s not just about the email content or the reputation of the domain / IP. Sometimes it can just be the tracking domain automatically added in your email’s HTML by your email sending tool.
For further info about this, check our article How to Prevent Emails From Going to Spam.
In all cases, when doing a deliverability test, you need to send your email exactly as if you were emailing your real target.
That means, when doing a deliverability test :
To know where your email will land, there’s only one way that really reflect the reality of your deliverability : sending your email to a significant number of inboxes and see where it lands. Period.
At MailReach, many people come to us saying “Hey, I don’t understand, my emails are landing in spam but I have 10/10 on Mail-Tester.
Breaking news : you can have 10/10 on Mail-Tester and land totally in spam.
Why? Because Mail-Tester does not tell your where your email lands. It’s mainly here to scan your email and see if you respect the best practices.
According to us, using Mail-Tester.com can be relevant to check if you’re in any blacklist, if your DNS records have been properly set up, etc.
But keep in mind that the best way to know your real deliverability and test your email for spam is by sending your email in real conditions to inboxes and check where it lands.
This one answers a very common problem we see nearly everyday at MailReach : a lot of people run deliverability tests and base their results on email providers that are not used by their real recipients.
It can totally bias the results since email providers don’t filter email the same way. And even inside Google, there are differences of spam filtering between @gmail.com addresses and paid Gmail (G Workspace). Same for Microsoft between @outlook.com addresses and paid Outlook (Office 365).
Let us explain that.
Let’s say you’re in the B2B area. The market share of email providers in B2B is around 60% for Google Workspace and 40% for Microsoft Office 365 (source : SuiteGuides).
This simply means that your recipients are either on Google Workspace or Office 365.
Thus, it’s really important to focus on these mailboxes when doing a deliverability test.
When testing your deliverability, if you land in inbox for all Google Workspace and Office 365 mailboxes, but are landing in spam in @gmail.com addresses, that doesn’t mean you’re doing bad.
For example, Gmail could recognize that your sending a B2B email to a @gmail.com address (generally used for B2C) and put it in spam because that’s not consistent according to their “rules”.
In all cases, we recommend that when doing a deliverability test, focus on the inbox services used by your recipients.
Every email in spam equals to a lost potential customer. Start improving your inbox placement today with MailReach spam testing and warmup.
Following the rules isn’t enough—know where your emails land and what’s holding them back. Check your spam score with our free test, and improve deliverability with MailReach warmup.
Without the right warmup, your best campaigns are of no use. You can start by first testing your inbox placement and begin improving it today.
Regularly running a deliverability test is one of the best practices to avoid the spam filters and improve your deliverability. At MailReach, we’ve seen that most of the time, deliverability testing is often done in an incomplete or biased way. In this article, we’ll cover how to properly run a deliverability test and check if your email will land in spam, categories or inbox.
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