Check for Spam before sending your campaign

Now, even after taking all the possible precautions, how do you know for sure, right?

The best thing you can do to avoid triggering spam filters is to check your campaign before sending it out.

Some ESPs perform an automatic spam check on all campaigns for you. Aweber gives you a “Spam Score” you can check before sending:

Aweber spam score

And it provides a breakdown so you can see the issues to fix.

Aweber score breakdown

Other ESPs don’t do it automatically, but they offer the option to perform a spam check on a specific campaign before sending. Here is how to check for spam on Mailchimp:

But, there is something even more important to consider when you want to make sure your campaign is not running the risk of being flagged as spam.

Not all tests are created equal

A spam check runs your campaign through different filters to see the potential issues. This is like sending your campaign to different email clients to see how it looks, before you actually send it and upset half of your list.

There are 2 types of filters:

Server-side filters (3rd-party filters that are widely used by the major email clients)

  • Barracuda
  • MessageLabs
  • Postini
  • SpamAssassin

ISP Filters (ISPs also have their own filters)

  • AOL Mail
  • Gmail
  • GMX
  • Outlook
  • Yahoo! Mail

The main question here is: What are you testing for?

For example, the Aweber and Mailchimp tests use SpamAssassin, and while this is the most popular, it would also be beneficial to test against the other filters.

Mailchimp test

3rd-party tests

You’re not limited to what your ESP offers, there are also 3rd-party services that perform spam tests. The image below shows a sample test from Litmus:

Litmus spam test

And here is a similar test from Email on Acid:

Spam test from Email on Acid

Both Litmus and Email on Acid are paid options. $79/month and $45/month for the basic packages.

Free options

If the paid services are out of your budget, you can still use some of the free options out there:

Here is how they work (I’m using Mail-Tester on the video).

These services are also based on the SpamAssassin score.


So, we mentioned SpamAssassin a few times already. What do you say we look into what it is and how it works. There are 3 things you should know:

Don’t worry too much…

As advised in its own website: “Don’t worry too much about specific rules within SpamAssassin. The rules catch spam. If your email isn’t spam, you shouldn’t be matching the rules. Even if you do hit an occasional rule, unless your email actually is spam, it shouldn’t score high enough to be a problem.”


FP stands for “False-Positive.” See, the SpamAssassin score is upside down, meaning that the lowest score the better. A “Positive” is a point against you, and when your email gets flagged as spam due to a system failure, it’s called a “False-Positive.”

As you can see, this is a thing, and it actually happens. This is why people that are NOT spammers, like you, need to know this stuff.


Here’s what you need to know about the score: You are safe to send your campaign with a score of 5 or lower (Remember this thing is upside down). Now, you also need to understand that this is just software, and there is nothing guaranteed.

Just because you follow doctor’s instructions doesn’t mean you won’t get sick.


I think it’s safe to say we arrived to one conclusion: No campaign should be sent out without testing it first.

  1. Find out how to check for spam on your campaigns with your ESP (I’d worry if they don’t offer this)
  2. If not provided, decide on using a 3rd-party service
  3. Run your test on the next campaign and look for the issues
  4. Fix the issues

Most importantly, you should get used to running a spam check on every single campaign you send. Make it part of your campaign checklist.