Jul 28 2014

16 Ways To Get Your Email Past Spam Filters

Spam filters are often overlooked, undervalued programs working hard to make us happier and more productive. They keep our inboxes clean and we barely ever notice them. But like all things designed by humans, spam filters are not perfect. The reason we love them as subscribers is the same reason we hate them as senders; they are very protective of the inbox. And for all of the good they do, we usually only notice them when they block our email campaigns. It's painful to see our hard work end up in the spam folder. We all want our email to get delivered. To get past spam filters you must first understand what they do.

What Is A Spam Filter?

Spam filters are programs that identify unwanted or unsolicited emails and prevent them from reaching inboxes. Major ISPs like Google and Yahoo! have built-in spam filters and filtering processes to ensure their users are protected from "junk" email.

How Spam Filters Identify Spam

Spam filters identify spam based on a long list of criteria, but generally they consider:

  • Relationship with subscriber
  • Reputation of IP address and sender domain
  • Quality of email subject line, teaser, and content
  • Quality and safety of links in email
  • Presence or absence of images
  • Ratio of images to text and links to text
  • Inclusion of text version of email

This isn't even close to an exhaustive list of factors that spam filters consider, but these are likely the most important. The list of spam factors is growing, because spam filters track subscriber actions to become better at identifying spam. Spam filters track the following subscriber actions:

  • If subscriber opens email or not
  • The amount of time subscriber takes to read email
  • If subscriber scrolls to bottom of email or not
  • If subscriber enables images
  • If subscriber flags email as spam
  • What tags subscriber applies to email
  • What folders subscriber adds email to
  • If subscriber forwards email
  • The number of times subscriber opens email

Tracking subscriber actions gives spam filters valuable data to shape their complex ranking formulas. Spam filters use these formulas, comprised of weighted spam factors, to determine an email spam score that is unique for each email to every individual subscriber. Sound complicated? This simply means that the same email for two different people could be ranked differently. Spam for one, ham for another. Spam filters rely heavily on subscriber engagement to learn how to become better at identifying what is and isn't spam for each individual subscriber. How Spam Filters Deal With Spam Spam filters use the spam score to determine what action to take next. An email with a passing score moves to the subscriber's inbox. If an email is flagged as spam, filters generally take one of the following actions:

  • Send email to spam folder
  • Block or bounce email for policy reasons
  • Slow delivery rate from sender (stuck in a tar pit)
  • Block email from sender
  • Block email from IP address
  • Block all emails from a range of IP addresses

Big ISPs such as Google are good at identifying spam on a case-by-case basis and sending it to the spam folder. But no spam filter is perfect. It is impossible to guarantee that every opt-in email will make it to the inbox of each subscriber. However, there are steps we can take to give our email a good chance of reaching our audience.

Let's dive right in...

Tactic #1: Produce quality email content.

The best way to get past spam filters is to send high quality email to people who know you and expect to hear from you. If you give people what they want and expect, you can expect healthy subscriber engagement. You also want to take care of the following:

  1. Clean coding.Coding yourself is not for faint-hearted because it is incredibly difficult to code email by yourself. If you don't want to do it, use ExpressPigeon's drag-and-drop editor which produces clean, 100% compatible code for you.
  2. Professional formatting.CAPS LOCK, dozens of exclamation points, and wild colors should be avoided. BELIEVE ME!!!!!!!!!!!!!!!!
  3. Wise words.Avoid spammy words and phrases. Don't mention getting rich quick or making tons of money or getting free everything today.
  4. Healthy linking.Don't send emails with 40 links and minimal text. This is a popular tactic by spammers. Keep a balanced text to link ratio.
  5. Balanced images.Spammers often use images to send 'special offers' because spam filters can't read them easily. Emails that contain a large image and very little text are often filtered as spam. Keep a balanced text to image ratio.

Tactic #2: Read and understand the CAN-SPAM Act.

The CAN-SPAM Act is a US federal law passed in 2003 that sets the rules for commercial email. With fines as high as $16,000 for every email that violates the law, it's worth understanding. I'm not your lawyer, in fact I'm not a lawyer at all, but below are a few general tips on how to comply with the CAN-SPAM Act:

  1. Do not deceive.Never use deceptive headers, subject lines, reply-to addresses, from-names, or call-to-actions.
  2. Make unsubscribing easy.Include an unsubscribe link, which must stay live for at least 30 days after sending. Remove unsubscribes within 10 days of opt-out. (At ExpressPigeon, we honor instant unsubscribes.)
  3. Include your real mailing address.You must include your actual physical postal address in your email.
  4. Never send without consent. Use our subscription formsto help people subscribe.

To learn more, visit the FTC website.

Tactic #3: Use double opt-in.

When building a signup form for your email subscription, you have the option with ExpressPigeon to do single opt-in or double opt-in. We recommend double-opt in, a process that looks like this:

  1. User subscribes for emails via signup form on your site.
  2. User receives email with confirmation link.
  3. User clicks a confirmation link and is added to your email list.

Double opt-in protects your list from bots and ensures that your subscribers are real people who want your emails. People who are more committed are less likely to flag your future email as spam. When you get a new subscriber using double opt-in, we collect the following information:

  • Timestamp
  • IP address
  • Browser
  • Operating System

This information protects you. If a subscriber marks you as a spammer in the future, we have a record to prove that permission was given. Using double opt-in is a simple way to increase the odds of getting your email delivered.

Tactic #4: Grow your list ethically.

Misleading or deceitful list-building tactics can crush your deliverability. Why? People who don't explicitly give you permission to receive your emails don't want to hear from you. They are likely to mark your email as spam. A few examples of what not to do:

  • Add all of your contacts to your list.Every person you know does not necessarily want your marketing email. Give connections, customers and friends an option to subscribe for email before adding them. Send them a nice invitation.
  • Use shady offline list-building tactics.People who drop a business card in a fishbowl or sign up for a chance to win a trade show giveaway do not necessarily want email from you. Be clear when collecting emails. There are healthy ways to build an email list offline.
  • Buy an email list.It's a really bad idea to purchase or rent an email list. Not only is it illegal and punishable by US law, it can crush your email marketing program and do long-term harm to your brand.
  • Scrape websites for email addresses. It goes without saying that this will only get you in trouble. Do this, and you'll probably end up on blacklists.

To get past spam filters, you want to attract people who are truly interested in your email. There are hundreds ofhealthy ways to grow your list.

Tactic #5: Design professional-looking emails.

If your emails look cheap or unprofessional, you can come across like a spammer. Check out our newsletter templates for inspiration.

Tactic #6: Craft relevant and engaging subject lines.

Spam filters and your audience don't want misleading subject lines. Make sure your subject line engages subscribers and tells them what your email is really about. Avoid spammy phrases like "click here" or "open now" or "act today" or "limited offer". Also, don't use ALL CAPS or too many numbers or special characters. Use our teaser feature to extend your subject line and entice people to open the email.

Tactic #7: Personalize your email.

The more you personalize, the better. The least you can do is address your subscribers by their names. Use the following text in a subject line or body or an email to do so: Hi, ${first_name} Subscribers appreciate receiving an email with a personal touch. The better your subscribers know you and trust you, the less likely they are to flag your emails as spam.

Tactic #8: Use a human reply-to address.**

Your reply-to address should be a real company email connected to someone human who your subscribers can communicate with. Avoid using an address like do-not-reply@yourcompany.com. This sends a selfish message to your audience and limits the possibility for healthy two-way communication.

Spam filters try to block phishing attacks, where attackers encourage readers to click on a well-known text URL that links to a different URL (attacker website). For example, a victim of a phishing attack would see "http://chase.com" in an email but upon clicking the link, they would be directed to "http://attackerwhostealsyouridentity.com". Because of this shady tactic, you should avoid using URLs as link text. Instead, use descriptive text. Every link in this blog post is an example of descriptive text. Here at ExpressPigeon, we offer phishing attack and composer protection to make sure you never forget.

Tactic #10: Start sending email right away.

You should be sending email the minute you get your first subscriber. Why? If you wait until your list reaches a certain size before sending, your first email will seem like a total surprise to early subscribers. And what do subscribers do when they are startled? They mark emails as spam. Instead of being stagnant, jump-start your list and send email from day one.

Tactic #11: Be consistent with send frequency.

If you don't send emails for long periods of time, and suddenly send, subscribers may forget about you and mark the email as spam. If you're sending too often, subscribers may get irritated and ignore you completely. Finding the right frequency for your email program requires testing, but consistency is key. Once subscribers know how often you send, they expect to receive emails at the same rate moving forward. When you meet their expectations, subscribers are more likely to become engaged readers and less likely to mark your emails as spam.

Tactic #12: Use a corporate email account as your sender address.

If you use a major ESP and send email using a personal email address such as paul@yahoo.com or paul@aol.com, ISPs like Google will block your email. Why? Yahoo! and AOL tell them to! The solution is to use your corporate email address or owned domain. Learn more about DMARC and what it means to marketers.

Tactic #13: Avoid spam traps.**

If an email address hasn't been used in years, ISPs sometimes convert that email address into a spam trap, called a honeypot. You will never know if an email address is a spam trap. The best way to avoid spam traps is to never scrape websites or buy rented lists. As long as you follow ethical list-building tactics, you should be fine. We recommend running a reengagement campaign every six months to make sure you have a healthy, engaged list.

Tactic #14: Make sure you are not on blacklists.

ESPs advertise which IP addresses they send from. Reputable ESPs (like ExpressPigeon) track this themselves, so you don't have to worry about it. If you are sending from your own IP address, you can use tools like MX Toolbox to verify and get alerted if your IP gets on a blacklist.

Tactic #15: Include a text version of your email.

It's easier to hide shady call-to-actions in HTML than it is in text. Even if you know people are not opening up a text version of email, it's not a bad idea to include it. At ExpressPigeon, you can easily convert your HTML design to text. We offer a simple "Text Version" button that allows you to pull the text from our drag-and-drop editor. Nowadays, most spam filters are advanced enough to dig into HTML, so including a text version is not as important as it once was. However, adding a text version can help you if you have subscribers using outdated email services or text-only reading settings.

Tactic #16: Use a reputable email service provider.

The best thing you can to do to get past spam filters is to use a reputable ESP like ExpressPigeon. We work hard to make sure your emails get delivered. You can try ExpressPigeon for free.


Getting past spam filters is a complicated process, but it foundationally comes down to sending useful email to an interested audience using a reputable email service provider. Beware of anyone who tells you otherwise. They might be out to spam you. ;) If you have any questions, feel free to leave a comment below or send us an email.

Happy mailin!