How to avoid spam filters and reach the inbox

April 10, 2018

Have your open rates suddenly plunged to single digits without warning or explanation? Don’t panic! Your subscribers still love you. They simply didn’t get a chance to open your newsletter.  Why?

In 99% of these cases, your plummeting open rate is a result of your newsletter accidentally ending up in that nasty place we call the junk folder.

We know your newsletter is not junk. But unfortunately, it was flagged by a spam filter. This is a frustrating experience because there is not always an obvious reason why the filter put your newsletter into the wrong folder.

Your subscribers want to open your newsletter, but they need to receive it first. In this blog post, we will share some of the best ways to avoid spam filters when sending your emails.

First off, what is a spam filter and how does it work?

Believe it or not, spam filters are your friend. Unsolicited emails, commonly known as spam, are a huge problem. There are over 200 billion emails sent on a daily basis and 59% of those are spam!

You don’t want all those bad emails competing with your valuable newsletter in your subscriber’s inbox. That said, spam filters are not perfect and often flag good emails.

A spam filter is basically a program that uses various criteria to determine if an email is spam. Some of these protocols focus on different aspects of the email such as:

  • Email Header – Filters email headers that use false information
  • Content Filters – Looks for common words associated with spam
  • Blacklisted Addresses – Blocks all emails from known spammers
  • User Permissions – Email owners define specific rules to block emails they don’t like

These are just a few of the ways that spam filters analyze your emails. The important thing for you is to do everything in your power to avoid these spam filters and end up where you belong – your subscriber’s inbox.

Here are 4 things you can start doing today that will help you stay away from that nasty junk folder.

How to avoid spam filters when sending emails

1. Send newsletters from your own domain


It’s perfectly fine to send emails to your friend or colleague from domains like,,, etc. However, when it comes to bulk email delivery, it is not a good idea.

You should always send newsletters from your own domain.

Why? Because MailerLite works closely with mailbox providers, such as Gmail and Yahoo Mail, to whitelist your domain or IP address. If you send bulk email from other domains, you are running the risk of sending your newsletters straight to the junk pile.

You should also avoid making frequent changes to your “From” field names, and don’t use strange names like “”. Use clear and reliable names like “newsletter@”, “support@”, contact@”, or “feedback@”.

The best approach is to personalize your address using a real name, e.g. Read more about personalizing newsletters.

2. Authenticate your domain

Authenticate your domain

Ok, you followed step one and added a personal email address like to the sender field. That is a great start. But before you push send, there is one more step to optimize your domain. It’s called domain authentication.

Domain authentication is a method to legitimize your bulk sending domain with our servers so they can send emails on your behalf. This helps spam filters tolerate your bulk mailing and validates your domain.

We wrote a short guide on how to authenticate your email with MailerLite.

3. Check your newsletter content

spam filters - Newsletter content

As we mentioned earlier, spam filters are always checking your content. They don’t have the human ability to analyze words in context, so they basically flag any words or phrases associated with spam. If they find a spammy word, they are nastier than Chuck Norris.

While there are no magic keywords to improve deliverability, you can limit the use of risky words to reduce the chance of landing in the spam folder. Here are some useful tips to check your email for spam content:

  • Link only to legitimate sites with reputable domains. Check all your affiliate links to ensure they are above board.
  • Don’t go crazy with email length. Spam filters don’t like newsletters that are a mile long. There is not a perfect newsletter length. But if you have more than 200 words or the reader has to work hard to get through it, shorten it.
  • Balance your images and text. Spam filters see images as blank space. If you send a newsletter with one large image and no copy, they will consider it as an empty email and your days will be numbered.
  • Don’t use too many exclamation points!!!!!!!!!!!!!
  • Avoid writing text in red.
  • Make sure you are not writing in ALL CAPS. IT FEELS LIKE YOU’RE SCREAMING! Nobody likes that.
  • Avoid fishy phrases like “Please click here”, “Don’t miss this!”, “This is not spam!”, etc.

4. Never use purchased lists!

Subscriber list

It is not just you. Everyone is tempted to grow their list by 100,000 potential customers by simply buying a list. If you are still considering this idea, stop!

Purchased lists are like ticking time bombs. Sooner or later they will destroy your reputation. Filled with non-existing email addresses and spam traps, they quickly inform mailbox providers that you like to break the rules by sending unsolicited emails.

Your messages will end up in junk folders. Even worse, you may be marked as a spammer.

To send an email using MailerLite, the recipient must be someone who has specifically asked to receive your emails by opting in or signing up in some way. If you are an online business, it can also be someone who has bought a product or service from you in the past 18 months.

Follow these 4 basic tips and you will avoid most spam filters and keep your open rate healthy.

P.S. Here’s a bonus tip: when confirming or greeting your new subscribers (e.g. via a welcome email), ask them to add your “From” address to their contacts. It is a clever way to bypass those spam filters. It never hurts to ask and it is highly effective.

Editor’s note: This post was originally published in January 2015, but has been revamped and updated for accuracy and comprehensiveness.

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  • Thank you so much for this very useful..

  • Thanks for this article Silvestras – very useful ;)

  • Thank you Silvestras, very useful article. Although we though mass email services like Mailerlite bypass spam filters and it’s 100% guaranteed inbox.

  • Hey,

    Thanks for your comments! Happy to see it’s been useful for most of you.

    Sam – nobody can guarantee 100% inbox, it depends a lot on things like your content, domain reputation, inbox settings.

  • Lina

    very useful, thx for the article

  • sooraj


  • Good tips, Silvestras!

    FYI: I was able to do the Authentication and DNS Records update easily with HostGator.

    Now need to do my first enews prep for new site.

  • Very Useful, to grow open rate & Increase business

  • Tahoura

    Thank you very much for your useful post.

  • Thanks a lot for this helpful guide.

    Hopefully we will manage to avoid the ”The No Man’s Land” Gmail Promotions Tab.

  • Ludovic: Gmail has changed the way it filters emails into categories. Most business/promotional emails will be read by the gmail filter and sorted into the Promotions category. This is NOT like going to the junk folder. This is simply putting your email in a place where readers expect to see promotions and business communications.

    Unfortunately this is not something that we can control, however, we view this change as a good thing for email marketing! Readers expect to see your emails there, and will check it out. Unlike when your email is mixed in between some personal emails and it gets passed over.

    Fear not! The promotions folder will help your open and click rates.

    Please note- you can put a small suggestion in your newsletter that will help your email hit their personal folder every time.
    “If you would like to see our email updates in your primary inbox, please drag this email from the Promotions tab, to the Primary tab. You will see our emails there from now on.”

    • Kasia

      This is not a good thing. I never read anything from my Promotions folder. I’ve asked my readers to drag and they don’t do it. Period.

      • Indica Snow

        @Kasia – I have used Gmail for a decade now, and I love the promotions tab. I read from it all the time. So don’t assume that an email in it is doomed to be ignored and deleted. It isn’t, I promise.

        • Elaine Calloway

          This may just be a preference thing. I never read things in my promo or social folders in gmail, only the inbox.

    • Ziga

      “Fear not! The promotions folder will help your open and click rates.”

      Come on, you just cannot be serious with that :) There is a 2-3x difference in ORs and CRs.

      Primary inbox delivery is still perfectly possible today also with campaign e-mails, just much more difficult, and sadly not possible using ESP’s like mailerlite that do no not provide an option for dedicated IP address, meaning your sender reputation is never 100% in your hands.

      This would be a feature that would get a lot of higher volume senders to the platform!

  • Thank you very much :D

  • I was looking for it and it is very helpful. Thanks for sharing!

  • Marc

    Thanks to such a great post! The tips herein would be helpful. I wonder if ML could integrate a Spam Score feature in future as it would be very handy to improving deliverability.

  • Nathalie S (mentorless)

    Hi, thank you for the update. I did notice a drop in email opening, even though I keep deleting subscribers who never open my emails. One element caught my attention in your post: the tip about not writing anything in red, which is the only element I can see as problematic. A year ago, I changed my hyperlinks from blue to red. Do you think this could have an effect? Thanks in advance.

  • Tatjana Vasichkina

    Great article :) Thanks to Silvestras, it’s really useful one!
    And thanks once again for the style of the article, I smiled while reading :)))

  • Very Helpful. It actually helped. But I don’t understand whats with the color Red?
    Is there any harm using it?

  • jenefa de souza

    firstly I’ve never taken stock of spam situation I am over it
    secondly its a eye opener to all Mailer lite users excess granted
    finally I’m thrilled to announce a potluck and makeover 2 u on my site

  • Howard Milstein

    Am currently going through some problems with gmail spoof and Mailerlite
    My dksm and spf are active… does that mean they are AUTHENTICATED? ( your rep said in effect – no – wait a bit more… sounds ludicrous?)

    However, yesterday- sent a small campaign
    Out and strangely, when tested to myself – I got spoof on gmail desktop- not mobile.??
    Other addresses seemed fine ( wife’s aol) but this I tested on mobile only.
    Can you figure what might be going on??