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Spam Test : How To Do It Right in 2021

Damien Breneliere - MailReach

Damien Brenelière

Co-Founder @ MailReach & Email Deliverability Expert

Doing spam tests 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, spam testing is often done in an incomplete or biased way. In this article, we’ll cover how to properly test if your email will land in spam, categories or inbox. 

Spam Test - How to do it right | MailReach

A proper spam test has to be done in real sending conditions

We’ve seen so many times people do spam tests and wonder why their results are so different than the reality of their campaign statistics.

Do you know 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 spam test, you need to send your email exactly as if you were emailing your real target.

That means :

  • Use your email sending service to send your test email
  • Send the exact same content you plan to send to your recipients
  • If you have personalization variables (e.g. “First Name”, “Company”), then replace them with values (e.g. “Franck”, “AB Consulting”). But of course, don’t take the risk of using potential spam words or it will screw your results.

A real spam test needs to be done by sending your email to several inboxes

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.

Why are we saying this?

Because we often see people saying “Hey, I don’t understand, my emails are landing in spam but I have 10/10 on Mail-Tester.

Breaking news : a lot of people 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 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. 

A relevant spam check should be done towards the inbox providers that your recipients use 

This one answers a very common problem we see nearly everyday at MailReach : a lot of people run spam tests and base their deliverability 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 addresses and paid Gmail (G Workspace). Same for Microsoft between 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.

Given that, it’s really important to focus on these mailboxes when doing a spam test. 

When testing your email for spam, if you manage to land in inbox for all Google Workspace and Office 365 mailboxes, but are landing in spam in addresses, that does not mean you’re doing bad. 

For example, Gmail could recognize that your sending a B2B email to a 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 spam test, focus on the inbox services used by your recipients.

Start improving your email results now.