11 Tips to Make Sure Your Emails Avoid Spam Filters – Essence of Email
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11 Tips to Make Sure Your Emails Avoid Spam Filters

Emails ending up in a spam folder instead of a recipient’s inbox is perhaps the worst nightmare of online marketers. 2017 Deliverability Benchmark Report by Return Path found that 20% of all commercial emails end up as spam. The truth is, not many of us spend valuable time going through the spam folder, looking for emails with appealing content. For that reason, it is essential that your audience sees the content you deliver to be able to engage with it. Here’s how to ensure that your emails do not end up as spam.

1. Set up Double Opt-In

Once new subscribers are added to your newsletter list, send them an email asking them to confirm that they actually want to receive emails from you. Having double opt-in helps you keep your list clean, ultimately improving your sender reputation. Whitelisting sends a clear signal to ISPs that subscribers on your list want to receive emails from you.

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2. Keep Your Email List Clean

Internet Service Providers (ISPs) determine your sender reputation by taking into account bounce rates, therefore, you should remove hard bounced emails from your mailing list. Dormant subscribers who do not open or click your emails might also damage your domain, which has an impact on deliverability rates. To make sure this does not happen, you should launch a re-engagement series. It will result in dormant contacts re-engaging with your content or being suppressed from your list.

3. Make It Easy to Unsubscribe

Having an unsubscribe link makes it easy for those who do not want to receive emails from you to opt out, and it is also legally required from you by the CAN-SPAM Act. Having people unsubscribe does not hurt your sender reputation in any way. However, having them mark your emails as spam does way more damage. Make it easy for them to unsubscribe, so they don’t have to choose the other option.

4. Do Not Use Spam Trigger Words

An enticing subject line will do a lot for your email marketing. Catchy subject lines can get you high open rates, but you should be careful of the wording you use. Spam trigger words will cause your emails to skip recipients’ inboxes and will land them in their spam folders, damaging your sender reputation. Some of the spam trigger words you should avoid are: guarantee, congratulations, winner, great offer, order now. Prospect.io provides a list of 455 spam trigger words to avoid.

5. Capitalization Is Not the Way to Go

Using uppercase letters in online communication is perceived as shouting and is usually considered to be rude. Emails with subject lines in uppercase look unprofessional and will most likely annoy your subscribers, resulting in being marked as spam by the recipients. Furthermore, these emails are a great way to trigger spam filters, damaging your deliverability rate. It is just too much of a risk to take. You can capitalize first letters of words, or perhaps one word you feel should be emphasized, but that is as far as you should go.

6. Do Not Include Attachments in Your Emails

Using attachments in your emails will land them in your recipients’ spam folders. This is because those who send out blast emails with attachments typically tend to be spammers. Apart from this, by adding attachments to your emails, your message becomes too large, increasing the time it takes for your emails to be sent. This can cause delays in recipients receiving your emails, ultimately affecting campaign performance. You can still share the content that would otherwise be attached in the email by linking it in the body copy or CTA.

7. Choose a Reputable ESP

To make sure you build a good sender reputation, you should do a proper research before choosing your Email Service Providers (ESPs). ESPs which send reliable and trustworthy content are also the ones deemed trustworthy. However, if an ESP allows anyone to upload lists of contacts without quality control, chances are that such an ESP will attract spammers. Build a good sender reputation by choosing an ESP which has built good reputation based on the good reputation of their clients.

8. Authenticate Your Emails with SPF, DKIM, and DMARC

By authenticating your email you are verifying yourself as a legitimate sender, thereby decreasing the chances of your emails landing in spam folders. Needless to say, ISPs trust authenticated senders more and are more likely to deliver your emails into the inbox. SPF or Sender Policy Framework helps you prevent spammers from sending messages on behalf of your domain. DKIM or DomainKeys Identified Mail helps you prevent email spoofing on outgoing emails. Lastly, DMARC or Domain-based, ensures that a legitimate email is properly authenticating against SPF and DKIM standards. If this is getting too complicated and you need help setting things properly so you can run spam-free emails to your customers, schedule a call with our email experts.

9. Use a Recognizable Sender Name

Most of us are more likely to open emails coming from known senders. An effective sender name will be consistent, making it easy for the customers to align it with your brand. Sender names which have a format like [email protected] are always a good way to go. Make sure you do not change your sender name frequently and you do not use obscure sender names. Both of these would confuse your customers, making them more likely to mark your emails as spam.

10. Test Your Emails

Testing your emails is always a good option. It makes it easier for you to see what kind of customer experience you offer, and in line with that, provides you with steps to improve your email marketing program. There are several sites which allow you to test the quality of your emails by assessing how likely they are to land in spam folders. Mail-tester.com, glockapps.com, and isnotspam.com will alert you if your emails are likely to trigger spam filters.

11. Email Certification and Accreditation

You can get a sender accreditation issued by a third party. This acts as a guarantee that you are a legitimate sender. Third parties issuing certification and accreditation already have established relationships with many ISPs and spam filtering companies, allowing your emails to go past some of the spam filters all emails go through. This service is not free, but given that it will keep your deliverability rates high, it is definitely one you should think of investing in. WPMU DEV provides a review of the 5 most popular SSL authorities.


Spam rate does not necessarily have to trigger stress response in marketers the way spam words trigger spam filters. There are preventive steps you can take to make sure your emails land in your recipients’ inboxes rather than spam folders. Applying the suggestions listed above will undoubtedly bring you closer to building a good sender reputation, ensuring that the content you deliver to your subscribers is something they can easily engage with.

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