How to Avoid Spam Filters When Emailing Your List

Avoid Spam Filters

Spam is a major problem for email marketers. I don’t mean what we receive. It’s no secret that spam is a problem for everyone in the 21st century. Fortunately, spam filters are in place to cut down on the deluge, but that can be a problem for people like you and me who are sending safe, legitimate emails and need to avoid spam filters when sending messages to our subscribers.

Spam has become such a major issue that it has been addressed by several pieces of legislation. In the United States, we have the CAN-SPAM Act. In Canada, CASL (Canada’s Anti-Spam Legislation). In Europe, the GDPR has made waves. Clearly, it’s something we need to understand.

Internet Service Providers (ISPs) spend a ton of time, money and effort every year fighting against the torrent of junk emails meant for their customers’ inboxes. This is an excellent thing, and they are to be commended for their efforts. Unfortunately, innocent, well-meaning email marketers can get caught in the wake.

In 2016, ReturnPath concluded that only 79% of emails sent by non-spammy, perfectly legit email marketers actually make it to subscribers’ inboxes. Ouch. There are several reasons an email may not be delivered, but very likely a spam filter deemed the message unworthy.

If I’m not careful, some of my best, most valuable content can get caught in email filters if I don’t know how to avoid them.

Obviously, to avoid spam filters, don’t send spam. That goes without saying. This guide is in no way meant to help those who would abuse the system and try to bypass junk filters for illegitimate purposes. But, for the rest of us, what can we do to ensure spam filters don’t think our messages are junk?

Use a real sender name

Make sure your “From” name is an actual name – not just an email address or anything else. It’s critical to use a name that people will recognize. But further, this helps spam filters recognize that you’re a real person – not just an email address.

That extra personal touch goes a long way toward convincing both your readers and spam filters that you’re legit.

Some ESP’s are able to avoid spam filters better

Email service providers aren’t all created equal. Some provide better email deliverability than others. These providers have established, favorable reputations with spam filter providers and email services. Therefore, they are better able to get past filters when others may be blocked.

Never use a free ESP. As great as “free” sounds, you’re getting what you’re paying for: lower deliverability and poor performance.

Make sure to thoroughly investigate any email provider before signing up. Can they actually get your messages delivered, or will they be blocked because the provider you chose doesn’t have an impeccable reputation?

Get your “I’m not a spammer” certificate

Sometimes a second opinion is helpful. A company like ReturnPath can take a look at your email marketing habits and certify that you’re not a spammer.

Of course, anyone can say, “I’m not a spammer” but that claim doesn’t carry much weight unless it’s backed up by a third party. ISPs will take ReturnPath’s word for it. Yours, not so much.

Check email blacklists to see if your address has been blacklisted

If you’ve wandered on the bad side of email marketing, it’s possible your email address has been blacklisted as a known spam address. This can also happen for reasons beyond your control. If in doubt, use a tool like MxToolbox to check your email address and see if your IP address or email has been blacklisted.

Test your email’s spam score before you hit send

If you’re not sure how your messages might be treated by email filters, test them before you hit send. A tool like Mail Tester will scan your message and spit out a spam score. Use your spam score to determine what you need to change.

There’s no better time to find out if your email is spammy! Keep your score in the healthy range to make sure your emails get delivered.

Never buy an email list

Buying an email list sounds like a shortcut to success. But it’s anything but. In fact, buying a list is one of the fastest ways to destroy your reputation as a marketer and any business you hope to build.

On a legal level, buy a list is a violation of CAN-SPAM, and the EU’s GDPR. Both of which prescribe hefty fines for each and every violation. Ouch.

On a practical level, if you buy an email list you are as spammer, and you should be caught in spam filters. Think about it. You’re buying email addresses of people who never agreed to receive any sort of communication from you. You don’t care about their preferences. You just want your message in front of their eyes.

That’s spammer level. If that’s you, you have no hope of avoiding spam filters. Nor should you.

If an address hard bounces, remove it from your list

Over time, emails go dormant and fall out of service. Someone may sign up with a perfectly valid email that, later, is no longer valid. Or, perhaps it was never valid from the start.

Inevitably, you try to send an email to that address, and you get a “hard bounce” saying that address isn’t valid. Rude.

Now, there are several reasons this might happen. But no matter what the cause, all email addresses that hard bounce need to be removed from your list immediately.

Why? Email service providers and ISPs care very much about your hard bounce stats. If a large number of addresses on your list aren’t valid, they’re going to start wondering whether or not you actually had permission to email those contacts in the first place. They don’t care that these may have been valid addresses at one point. All they know is that you are now trying to message people who don’t exist – and that puts you in suspect territory, hurting your reputation as a sender.

Clean your email list to avoid spam filters

Proper email list hygiene is essential for avoiding spam filters. If someone doesn’t open your messages or is simply unresponsive, don’t be afraid to remove him or her from your list. If people don’t interact with your content, your email stats will suffer. If your email stats suffer, your sender reputation can take a hit. If that happens, your chance of getting past spam filters drops to about nil.

Use confirmed (double) opt-in

There are two (main) types of opt-ins we use today. Single and double. Unconfirmed and confirmed.

Unconfirmed (Single) Opt-In: A visitor fills out a form on a landing page and is instantly added to your list.

Confirmed (Double) Opt-In: A visitor fills out a form on a landing page, but before he is added as a subscriber, your email service provider sends a message asking him to confirm his subscription.

This comes with advantages and disadvantages.

People tend to be lazy (yours truly included.) Asking visitors to take an extra step and confirm their subscription will keep some people off your list. They won’t want to put in the extra 30 seconds of effort.

On the flip side, these people probably would have never purchased anything. They’re not engaged.

But more importantly, double opt-in prevents fake or invalid emails from ever getting on your list and causing hard bounces. How? An invalid email address can’t receive the confirmation email, and no one can click the confirmation link. If no one clicks the confirmation link, the email address is never made a subscriber.

Respect unsubscribe requests

Inevitably, some people will want to unsubscribe from your list. Don’t stress about it. It happens, and it’s normal. In fact, you actually want some people to unsubscribe. I know it sounds counterintuitive, but you do.

Now, when someone asks to leave, you have a couple of options:

A)  Let them leave. Respect the request and let them go in peace.

B) Keep them against their will. Keep them subscribed even thought they’ve asked to be removed.

In the first scenario, your subscriber is a guest. In the second, he’s a prisoner.

Aside from being an objectively terrible thing to do, morally speaking, keeping a subscriber against his will is highly illegal. The American CAN-SPAM act and the European Union’s GDPR both allow for extreme financial penalties for anyone who would misuse customer data in such a fashion.

In each piece of legislation, it is mandated that businesses use customer data in a way that aligns with customer preferences. A business may not retain and process data if a customer does not wish it. Further, a company may not use that information to market to an individual via email if he has requested otherwise.

If a subscriber continues to receive email from you after requesting to be unsubscribed, your reputation will suffer. Expect him to report you as spam to his ISP and other authorities – hurting your chances of maintaining a reputation as a legitimate businessperson. As more and more people report your illegal messages, ISP spam filters will learn that anything coming from you is spam.

The long and short of it is this: If someone asks to leave your list, you let him. You have no right to hold a subscriber hostage. Otherwise you will have zero hope if you want to avoid spam filters.

Spam filters check your words

To avoid spam filters, choose the words you use very carefully. Filters are smart. They know certain bad actors tend to use the same kinds of words. Their solution? Immediately flag any email that uses many of these known spam words.

Now, there are plenty of legit, honest reasons to use these words. But spam filters can’t always distinguish between a safe, legit use of a word and someone who is sending junk.

These words and words like them send up red flags because those sending junk tend to use them. Thus, if you use them, spam filters are likely to think you might be a spammer too.

That’s bad news for you.

Avoid rich media

Rich media can be fun. This includes videos, animations, even some graphics. They can add a nice visual touch to your messages. But the down side is, using these things may get you in trouble with spam filters.

If your videos don’t play, or your embed code isn’t right, spam filters will be quick to assume there is something wrong with your message – and thus with you. They understand that spammers tend to be lazy and sloppy with their code. So if they see that coming from you, it spells bad news for your reputation.

In general, I recommend avoiding rich media altogether. If you want to send your list a video, send a link to another website – like YouTube. Don’t try to embed it in the email itself and risk spam filters thinking the worst.

Avoid JavaScript and Flash. Spam filters hate them – and JavaScript especially may make antivirus software very suspicious.

But, that said, many email clients will have these things turned off by default, so even if you insist on including JavaScript or Flash, they most likely won’t even work! Don’t waste your time or risk the damage to your reputation.

You’ll be better off avoiding spam filters by sticking to simple text and basic graphics.

Don’t include attachments

Many of our information products are files – like PDFs. But these should not be sent as email attachments if we want them to reach their destinations. Spam filters are trained – like guard dogs – to filter out suspicious files. If your email address isn’t recognized by a spam filter, and the filter sees you trying to send a file, good luck getting through.

Any proficient IT professional will tell you that email attachments are often used to infect computers with viruses and malware. Even if your files are 100% safe and legit, a filter may not know that – and will be quick to refuse delivery.

Instead, it’s better to send a link to a website where your file can be downloaded.

For example, when someone signs up to receive my Info Product Tutorial ebook, I send him or her a link to download the PDF. This works well helps me avoid spam filters.

Don’t use too many images

A picture may say a thousand words, but not if it doesn’t reach its destination. Pictures are great. They add context and character to your messages. But if you use too many, you may not get through to your subscribers’ inboxes.

Like many things in this list, it’s not that images are inherently bad. The problem is spammers like to misuse them in their messages – which ruins them for the rest of us. Annoying. So, we have to work around the problem.

To avoid spam filters, it’s best to either not include images at all or to only include one or two in each email. If you go overboard, you will start to look suspicious to your subscribers’ email filters.

Avoid embedded forms

Forms are great when we need to get more information from a subscriber. Maybe we want him or her to sign up for an event or answer a question. But email is no place for a form. It’s not that forms are inherently bad – like images. But they have been misused and are now ruined for the rest of us.

However, in general, your subscribers’ email clients won’t be able to display a form anyway because the needed scripts are often blocked or turned off by default.

It’s best to send your reader to another website to fill out the form. Otherwise, spam filters will eat you for breakfast (or dinner, depending on your time zone.)

Be consistent with fonts and colors

Don’t use multiple fonts in your emails. Not only does it look sloppy, but it reduces your chances of making a positive impression on your audience.

Even worse, mixing fonts and styles signals to filters that your email may not be legit.

Watch your grammar

Spammers usually have notoriously horrible grammar. Spam filters have caught on. Unfortunately, that means if your English needs a bit more polish, you could easily be mistaken for someone who’s not legit.

Before you hit send, give your text a once-over. Make sure your point is clearly and concisely conveyed in a way that is grammatically correct.

Keep your subscribers happy

Hopefully your goal as an email list owner is to keep your subscribers happy. But if you want to avoid spam filters, you have another incentive to make sure they are happy and engaged.


If your subscribers – for whatever reason – decide your content is no longer relevant or worth their time, your email stats will suffer. As your open and click through rates suffer, your reputation can slip. As your reputation slips, spam filters will be more likely to decide you’re junk.

Further, some of your subscribers may mark your messages as spam if they aren’t high quality. “But wait, didn’t they subscribe? I’m not a spammer!”

True, but people are people. If they aren’t satisfied – for any reason at all – they could easily tell their ISP’s that you’re sending spam. If that happens, be ready for your deliverability to drop.

Don’t play games with spam filters

Spam is a real problem – not just for end users but also for marketers and businesses of all sizes. While you and I would never send spam, we need to understand how filters work so that our content isn’t wrongly flagged as malicious.

Even well-meaning, honest marketers can fall victim to overzealous email filters. So, we have to learn to play ball.

You could easily ignore my advice and just wing it. After all, you’re not a spammer, right? Unfortunately, that’s not how it works.