How To Avoid Email Spam Filters

Updated: August 7, 2016
by Ray Alexander

If your email newsletters or autoresponders have low open rates, chances are that they end up in the recipients' spam folder. There's no point in welcoming more subscribers and hoping the same emails will land in their inbox next time round. We need to fix this, need to know how to avoid email spam filters. So here are the list of things email marketers should remember to do.

How To Avoid Email Spam Filters

#1 Eliminate Forbidden Spam Words​

​Surprisingly or not, most of the "make money online" words and phrases are classed as spammy, including words such as "free" "work from home". In fact there are insane number of suggested words that should be avoided at all costs.

The following list is taken from GetResponse, gathered from several other sources.

  • A - C
  • D - G
  • H - N
  • O - R
  • S - Y

Safeguard notice
Satisfaction guaranteed
Save $
Save big money
Save up to
Score with babes
Section 301
See for yourself
Sent in compliance
Serious cash
Serious only
Shopping spree
Sign up free today
Social security number
Special promotion
Stainless steel
Stock alert
Stock disclaimer statement
Stock pick
Stop snoring
Strong buy
Stuff on sale
Subject to credit
Supplies are limited
Take action now
Talks about hidden charges
Talks about prizes
Tells you it’s an ad
Terms and conditions
The best rates
The following form
They keep your money — no refund!
They’re just giving it away
This isn’t junk
This isn’t spam
University diplomas
Unsecured credit/debt
US dollars
Vacation offers
Viagra and other drugs
Wants credit card
We hate spam
We honor all
Weekend getaway
What are you waiting for?
While supplies last
While you sleep
Who really wins?
Why pay more?
Will not believe your eyes
Work at home
You have been selected
Your income

So many phrases...! And really? Cannot use the word "Amazing" in my email...?

But I tell you what. This is what's suggested by professional email service providers and I follow what they say. I have gone through this list carefully, eliminated any listed words from my own email newsletters, and actually saw a remarkable result. Opening rate of 9% before then over 35% after (that's considered fairly good). For that reason, I personally pay my best attention to the words I use in each and every email I send out.

#2 Don't Include Attachments

Email attachment

Not many email marketing services give an option to include attachments. That is good. Emails with an attachment are most likely to be blocked by spam filters. If you need to send a document such as infographic in PDF file or Word document, upload it on your web space and give your recipient the URL.

Similarly, if you need to show your recipients a group of photos, compressing them in a Zip file and attaching it to your email may seem like an easy option, but that is also a big "no".​

Instead you can either upload all the photos on your web page and give your recipients the URL(s) and let them download. 

And I do receive email with attachments from time to time (I'm referring to bulk emails such as newsletters, not personal emails). They all end up in my junk mail folder. Check yours.

#3 Try Minimising Your Image File Size

Minimise image size

It's important to be aware that your email loads quickly at the other end, and that's another reason why no file should be attached to the email.

Using a large image in size, or too many images in one email will be considered spam. So you need to reduce the dimension or compress the image that you use.​

There are some free image compression tools - try or The latter also compresses PDF file which is handy for other purposes (such as uploading a PDF file onto your site).

#4 Subject Line Matters

"Viagra" (and similar trading names for sexual enhancement medication) is also considered as a spam-triggered word. That's not just for the subject line but within the entire email. I receive emails with the word "Viagra" in subject line often (is it just me!?), all of which are found in my junk mail folder. Equally, emails with meaningless phrases such as "Hi" "How are you?" in the subject line almost always end up as a junk/spam mail.

Check Your Spelling

It is also advised not to use "​Re" or "Fwd" in the subject line. You don't send out a newsletter to your readers as a reply, or forwarded message, do you?

Inserting "Re" "Fwd" in your subject line manually is an ancient dirty trick (them into believing that you've replied to their email) that no longer works.

#5 Check Your Spelling

Talking about Viagra, you may have seen "alternative spelling" such as Vi@gra​. Those spammers have been using the trick for many years, hoping they arrive in your inbox. No chance! They are just....annoying $hit!

Spelling checker

With that said, there's no such word as ​"Vi@gra" exits, meaning it's a mis-spelt word. Make sure that your spelling checker is in place and there's no silly mistakes here & there within your article.

DNS Stuff Email Test

#6 Are You Blacklisted?

Try this free tool to see if your domain is blacklisted as a spammer. There is a possibility if your domain has previously owned by someone else, or your hosting company is blacklisted. 

How To Avoid Email Spam Filters - I hope the above information is useful. Any questions please don't hesitate to leave a comment.

About the author 

Ray Alexander

ASD. Recovering alcoholic. LGBTQ+ advocate. Semi-retired. 15+ years of web-designing experience. 10+ years affiliate marketing. Ex-accountant. I'm nice and real. Ask me if you need any help in starting up your home business.

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