Email Getting Lost in Cyberspace? Try These 10 Methods to Avoid Spam Filters!

Familiar with the basics of good email design but emails are still getting lost in cyberspace? Spam filters hunting you down like you’re Sarah Connor? Most of us know by now not to use dodgy practices that attract spam filter attention like TYPING IN ALL CAPS, g a p p i n g w o r d s, and much abused keywords like FREE!!1!. If you’re avoiding common pitfalls already and still having a problem with spam filters, you need to consider more advanced strategies.

thearnoldWe’ve covered general properties of spam and spam filters previously here at We’ve also talked about how to improve the general reliability of your email practices. With this article we’re going beyond that general advice to look at 10 detailed steps you can take to avoid spam filters. Let’s take a look!

A Quick Preface

Before we look at how to avoid spam filters, we need to put them into proper context. We’ve talked about the general function of spam filters previously in terms of individual programs. Do not think about spam filters as if they were separate entities acting in isolation, though. Just like the rest of the web, they’re interconnected.[1]

The interconnective element of the spam filter is the firewall. There are a number of companies that produce these: IronPort, Barracuda, CloudMark and others. Why is this important? Take Cisco’s IronPort as an example. You send an email that is mistaken for spam to a company using an Ironport firewall on their server. It reports you to SenderBase, Cisco’s email and web traffic monitoring network. This happens often enough and Senderbase pushes your information, flagged as a spammer, out to every server running IronPort the world over.

When you send email, you’re not just dealing with a single spam filter on a single server. If you are not careful about your email practices and earn a reputation as a spammer, you can quite literally have the majority of the world’s doors slammed in your face. That can be bad for business!

10 Methods to Avoid Spam Filters

(1) Ask Permission

The single best surefire way not to be marked as spam is to only send emails to people that want them. There are absolutely lists you can buy, sites you can scrape (illegal, fyi), and other methods that will get you large email lists fast. If you are a legitimate business that cares about brand and image, this is a fast way to tank that perception and will land you on blacklists around the world.

What’s called the double opt-in method is the best practice for building your contact lists. With this method you gather emails via a form or similar medium that clearly communicates your intention to email that individual in the future. Follow up that form submission with an email that requests the user to opt-in before receiving future emails. Ninja Forms makes this very easy with email actions; you can set your form to automatically fire an email responses on submission with your opt-in message.

The double opt-in method removes any doubt that any individual that is added to your list wants to receive emails from you. Yes, it will reduce the overall number of adds to your list. Two points to consider that offset the loss: 1) you are populating your lists with a much higher quality of contacts with this method, and 2) it’s your reputation and possibly the viability of your business model on the line here. Quantity isn’t worth it.

(2) Use a Reputable Email Marketing Service Provider

mailchimpYour provider’s reputation is only as good as the reputation of its clients. As such, reputable providers go to great lengths to ensure their clients are not spammers. In turn, when a spam filter sees email originating from these providers, they do not garner as close a level of scrutiny as emails from less reputable sources. Some examples of service providers with great reputations around the world are MailChimp, AWeber, and Constant Contact, among others.

(3) Know the Laws Regarding Email Spam

The federal CAN-SPAM Act of 2003 sets the legal definition of spam and establishes rules and requirements that govern email and commercial messaging in the United States. [2] The CAN-SPAM act preempts most state law on spam, but certain states do have laws in addition to the federal requirements.[3] It is important to be aware of what applies to you. CAN-Spam has seven major requirements for compliance:

  1. Don’t use false or misleading header information.
  2. Don’t use deceptive subject lines.
  3. Identify the message as an ad.
  4. Tell recipients where you’re located.
  5. Tell recipients how to opt-out of receiving future email from you.
  6. Honor opt-out requests promptly.
  7. Monitor what others are doing on your behalf.

The application of CAN-SPAM with transactional email, such as those you’d be sending as an automatic response on form submission, is less strict than with bulk commercial email. I’m not qualified to give legal counsel so I’m not going to get into the intricacies, but do be aware of the law and do consult qualified legal counsel where it is prudent. The fine for non-compliance is $16,000USD per email. That can add up really quickly if you’re sending bulk mail.

(4) Take Advantage of Personalization Features

If you’re not familiar with the term whitelisting, it means having a name added to a list of known names that are ok to do business with. It’s the opposite of blacklisting: adding a name to a list of names to stay away from or block.

You want to be whitelisted with your recipients. It’s as simple as them adding you to their email contacts list. Ask for your From address to be added to contacts in your opt-in email or however else you feel is reasonable to handle it. Being whitelisted by your recipients reduces spam filter attention on those emails considerably. Good email service providers like the ones listed above in method #2 will also take the extra step of whitelisting your IP address and domain with major mailbox providers (gmail, hotmail, etc) for you.

Spam filters also look at email metadata like the To and From lines. Personalized metadata reduces spam filter attention. Personalizing the To field is as simple as adding your recipient’s name to contacts and addressing the email to their name rather than their address. Again, good email service providers will likely encourage you to do this in their setup processes anyway.

Personalize the From field with a clear and relevant name. A From field like,,, etc is going to draw less attention than something vague like or

(5) Include Plain Text Versions When Using HTML, and Optimize HTML for Email

htmlIncluding a plain text alternative whenever you send HTML email will reinforce the legitimacy of your email. This practice reduces the chances that your email is sentenced to oblivion by spam filters. It also ensures that all your readers, even those that cannot view HTML, have the opportunity to see what you offer.

Using HTML in an email is not the same as using HTML in a webpage. You need to be aware of the difference and able to shift gears when it comes to coding for email. See the footnote for a detailed look at the differences.[4]

(6) Optimize Your Content

The following are all important points that you need to consider when crafting your content.

Text to image ratio. Low text to image ratio is a red flag for spam filters. Keep text:image as balanced as possible. Aim for a few lines of text for every image, and keep the images reasonably sized.

lolcatImage Hosting. There are professional image hosting services out there. If you do not host your own images, find a reputable commercial host for any images you include. Using free public sites like Flickr or Photobucket risks earning you spam filter points.

Never use Flash, video, or gifs in an email. If you want your readers to view video, give them a link to it.

Do not send attachments. Extensions like .pdf or .doc won’t get a great deal of spam filter attention, but none is better than a little. Others like .exe or .zip will guarantee you banishment to the lower planes of cyberspace. Redirect your readers to your .pdf file via a link back to your website.

320px-Paperclip-01_(xndr)Minimize links and do not use url shorteners. There’s not much more to say about that. Url shorteners are a big red flag because it’s easy to hide a malicious url in shortened form. Too many links reek of spamminess. Like images, balance the number of links you have with the amount of text, but keep the ratio of text to links even higher. Also make sure that you link only to reputable domains or you risk guilt by association.

Spell/grammar check. Don’t nobody wnts 2 reed txt that looks liek wuz righten by a hi schooler, yo. In addition to appearing very unprofessional, misspelling common words and using poor grammar is an age old tactic to bypass filters that just doesn’t work anymore: v1agra, lose waight now, m0rtage qu0tez, Business want to infrom you to notify all online customers free gift for business anniversary, etc.

Be brief. Too much copy is another item on the long list of spam filter flags.

(7) Use a Spam Check Tool

There are a variety of free and paid spam checkers out there. These programs will take a look at your email for you as if it were a spam filter, and alert you to likely filter triggers. Mailingcheck is a popular free solution that uses the ubiquitous SpamAssassin spam filter protocols. If you’re using a top tier email service provider like MailChimp, you likely have an inhouse spam check option. MailChimp uses Inbox Inspector for spam checking and overall design evaluation.

(8) Offer a Very Simple Unsubscribe Option

It ought to go without saying that you must offer an opt-out or unsubscribe option in every email (see method #3 above re the CAN-SPAM act). No matter how awesome your newsletter is, there are going to be people who eventually want to unsubscribe. They have two options to stop getting emails from you: mark your email as spam, or unsubscribe through the option you’ve presented them.

It’s likely all the same to them which they use, so the bottom line is that your unsubscribe option has to be more convenient than kicking you into the spam folder. Make it obvious, make it quick, and make it idiot-proof. Burying the unsubscribe link or making the user jump through hoops to complete the process is shooting yourself in the foot. Remember that enough users marking you as spam can lead to your IP or domain being blacklisted; see the Quick Preface section at the top of the article if you need refreshing on that. Honor unsubscribe request promptly, or if possible make it automated and immediate.

(9) Keep in Touch with Subscribers and Keep Your Lists Up to Date

Emailing every day or even every week can become monotonous and annoying for your subscribers. On the other end of the spectrum, emailing only every two or three months or waiting for the holidays can cause them to forget about you and mistake you for spam they didn’t sign up for. Strike a balance and keep your emails regular and consistent.

Keep your lists up to date by reaching out periodically to inactive subscribers to confirm that they want to continue receiving your communications. Also, and more importantly, immediately cull addresses that bounce. Too many bounced emails can flag your IP and domain as a source of potential suspicious activity for filters.

(10) Monitor Your Brand Reputation

return-path-logo-700x497-400x284A variety of services exist that allow you to monitor your brand reputation. The last thing you want is to land on a blacklist in ignorance and have business decline without you even being aware of the reason. We’ll look at a couple to get you started.

Return Path is a an email optimization company that works with giants like BellSouth and Comcast to gauge the reputation of IPs and domains. The metric they measure reputation by is called Sender Score, and it functions similarly to a credit score.[5] Using their Reputation Monitor service, you can monitor your Sender Score yourself and learn how to raise it. They estimate that 83% of delivery failures on networks they service are caused by low Sender Scores. You can also have them periodically audit your email practices and grant you accreditation, which is a virtual guarantee of access to network inboxes.

DNSstuff is another service with a similar focus. They offer a variety of services for optimizing email:

  • Check blacklists to make sure you aren’t on them.
  • Monitor web, email, and name server compliance and connectivity.
  • Mail Server Test Center, which lets you manage and monitor email and perform real-time tests to troubleshoot configuration, connectivity, routing, and other issues.

peeking-ninja-300x138Congratulations on making it this far, it’s been quite a read. This article was originally intended to be a subsection of another article, but when it came right down to it I realized there was no way the topic could be done justice on that level. Spam detection and filtration is an ever evolving thing, changing with technology and innovation just like communication itself.

Staying on top of what it takes to be an efficient email marketer takes quite an effort, and a less in depth analysis simply would not have been an adequate reflection of that effort. Sifting through the web turns up dozens on dozens of articles with quick tips and tricks to avoid spam filters, but I am confident that these ten tips are among the most effective measures you can take to ensure maximum deliverability and reliability for your email. For further reading on the topic and some great examples of what good form vs bad form in email design looks like, check out Ms. Sapph Li’s article over at Good luck and may the spam filters miss you!