Helga Written by Helga

Detailed Guide: How to Protect Your Email Newsletters From The Dreaded Spam Folder

1. What is email spam?
2. Key Anti Spam Laws
3. Most Popular Spam Email Lists
4. What Do Spam Filters Look For
5. How to Prevent Email Newsletter from Going to Spam

Useful tools:
1. Newoldstamp - Email signature marketing
2. Mailchimp - Email builder and sender
3. Reply.io - Personal email outreach, calls, and tasks
4. RocketLink - Your branded short linker
5. Canva - Online tool for making designs

Whether you are a business sending weekly newsletters to hundreds and thousands of email subscribers or an individual sending just a few emails a week to a shorter list of people, you want those emails actually to reach the receiver. You don’t want this message to go into their spam folder, because there are some solid odds they won’t find it. Well, let’s try to figure out why your email can go to spam and how to prevent this from happening.

What is email spam?

It is an irrelevant unsolicited email sent to a large number of people who, as a rule, did not choose to receive it. For example, Mr. X purchased a list of email addresses to spread a word about the launch of his new software. At first sight, that list of contacts may seem like it could contain some useful prospects for Mr. X’s business, and he wants to send them an email with a relevant offer they cannot refuse. However, those people didn’t give him explicit permission to contact them. Therefore, sending a newsletter or any other content to that list would be considered as spam.

Key Anti Spam Laws

To combat spam emails, many countries around the world have enacted anti-spam legislation. For example, if your audience is located in the United States, you have to follow the CAN-SPAM Act.

If you email someone from Canada, you need to be compliant with the CASL (Canada's Anti-Spam Legislation). Those are intended for people who are going to send commercial advertisements or promotional emails. While the regulations vary from country to country, most important elements are pretty similar:

  • You shouldn’t use false or misleading header information (names, reply-to addresses, subject lines);
  • It is obligatory to provide an unsubscribe link that must work for at least thirty days after sending;
  • You need to tell recipients where you are physically located;
  • Subscribers must have actively opted into your list;
  • If someone else (for instance, a marketing agency) is sending emails for you, you need to monitor their actions and ensure they don't violate the requirements of the CAN-SPAM’s guidelines.

Otherwise, you may be subject to heavy penalties.

Also, you might be interested in reading our recent blog post about the General Data Protection Regulation (GDPR) and how it will affect your communication with your European audience.

Most Popular Spam Email Lists


 image courtesy of senderscore

Getting blacklisted happens to a lot of email senders, especially if they deal with email marketing, and it is brutal because it has a direct impact on email deliverability. If you got blocked, it has been more likely caused by poor mailing list quality and a fair number of end-user complaints. To avoid email blacklists and spam folders, be sure to check if your IP address and domain aren't on any of these popular lists:

What Do Spam Filters Look For

spam filtres

image courtesy of junkemailfilter

Basically, most spam filters check your emails for certain "spammy criteria" like:

  • A subject is all capitals or a grammatically incorrect subject line
  • Spammy topics (for example, viagra, body enhancement, $1, 000 000 jackpot, etc.)
  • Links to untrustworthy resources
  • Too many images, and not enough readable text
  • The bad reputation of the sender
  • Low subscriber engagement
  • And more.

How to Prevent Email Newsletter from Going to Spam

If you want to prevent emails from going to spam, follow these tips:

Tip #1: Don't purchase or scrape your email list  

Stop buying email lists. Otherwise, you’ll end up in a spam folder. Also, you risk violating anti-spam regulations mentioned earlier in the text and may be fined.

Tip #2: Send email only to subscribed users

Your content is useless if you send it to the wrong audience.

Tip #3: Use double opt-in for newsletter subscribers

The double opt-in confirms that the user who entered their email address do want to hear from you. If there is no extra confirmation (single opt-in), then any user could enter somebody else's email address to sign-up. From the perspective of email list owners, the double opt-in is important because only people who genuinely want to be on their list are signed up.

Tip #4: Validate your email with SPF, DKIM, and DMARC

validate your email

image courtesy of uptakedigital

To ensure that your message is getting into the inbox of your customers, not into the spam folder, you will need to authenticate it with SPF (Sender Policy Framework), DKIM (Domain Keys Identified Mail), and DMARC (Domain-Based Message Authentication Reporting and Conformance). Those are email security standards for spam prevention. Nowadays, there is a variety of tools that can tell you if your mail campaigns are failing SPF, DKIM, and DMARC configurations. They are GlockApps, Mailtester, and others.

Tip #5:  Avoid spam words

avoid spam words

image courtesy of buzzfixer

Believe it or not, some words can trigger your email message as spam. Typically, those words are associated with sales: “free,” “no obligation,” “buy,” “promo,” “bonus,” “purchase,” “extra income,” “amazing,” “increase sales,” “increase traffic,” “winner,” “great offer,” “act now,” “success,” “visit our website,” “guarantee,” and so on. See more email spam words here. Also, be sure to use only one exclamation mark per sentence or better not to use them at all.

Tip #6: Link to trusted websites in your newsletter body

Did you know that spam filters check the URLs to which you are linking? If you choose to link to a domain that has a poor reputation, the chances email spam filters will block your message are pretty high.

Tip #7: Consider your image-to-text ratio

It is OK to include images in your email marketing campaigns, but never send them without text. For every picture that you send, write at least two lines of text.

consider your image to text ratio

image courtesy of reallygoodemails

Tip #8: Use only reliable image hosting services

Another reason your emails are not getting delivered to the recipient's inbox is that you host images on an untrusted domain. Find a reputable commercial host for any pictures you include. Some of them are your server, Google Photos, Amazon S3.

Tip #9: Limit your newsletter email size

Did you know that email size belongs to one of the spam filter criteria? Multiple studies conducted by email marketers show that the perfect email size doesn’t exceed 100 KB. But how do you make your newsletter lighter?

  • Use .png format instead of .jpg;
  • don't insert images in your message without any text;
  • try to avoid using attachments.

Tip #10: Use only ESPs with a good reputation

If the reputation of your ESP (email service provider) is poor, some of your emails won’t reach the inboxes of your recipients. To check your ESP's reputation, use Mxtoolbox or a similar website.

Tip #11: Receive certification

Email certification is a service provided by independent organizations that have special relations with numerous ISPs (Internet service providers) like Aol, Comcast, etc. and a lot of various spam filtering companies. So If you send emails in large quantities all at once, it is highly recommended to get certified to bypass some of the spam filters that every email message goes through.

Tip #12: Use a proper email address

A lot of spam filters are set up to look for numbers, superlative adjectives, and underscores in the sender's email address. To avoid ending up in the junk mail bin, use only clear and trustworthy from field names, such as: “info@abccompany,” “artphoto@gmail.com,” etc.

Tip #13: Whitelist your email domain

As we already mentioned above, it is crucial to use only reputable email marketing services, as they ask mailbox providers, such as Gmail or Yahoo Mail, to whitelist your domain and IP address. To be whitelisted with your recipients, you need to ask them to add your "from" address to their contacts. This will considerably reduce spam filters attention to your emails.

Tip #14: Check your email metrics


image courtesy of campaignmonitor

It is good to know if your email campaigns are performing well or require some changes. Therefore, you need to track:

  • Open rates

If you noticed that your open rate is low, you could assume that the content you are sending is "unwanted," or you haven’t clean your list of subscribers recently. Both can cause your campaigns to get caught in the spam folder.

  • Click through rates

The click-through rate helps you understand how many users are not only opening your messages but are also engaging with your content and taking the desired action.

  • Bounces

The bounce rate is a good indicator of the quality of your list of subscribers. In case your list is regularly generating bounce rates higher than 2-3%, it's a sign that you need to work on your email database more carefully. Pay attention that mailbox providers track bounce rates for every email campaign you send out. Based on the information received, they decide whether your emails will go to the recipients’ inboxes or spam in the future.

Tip #15: Regularly clean up your email list

Let's be honest, unengaged subscribers on your list are useless. Try to keep only the recipients who regularly open, read, and actively interact with your content. The better the deliverability, open rates, and click rates are, the more successful your future email campaigns will be.

  • Use email validators
  • Deactivate your inactive subscribers
  • Deactivate your bounces

Tip #16: Include your physical address

physical address

image courtesy of reallygoodemails

To be compliant with anti-spam laws, you must include your physical address in the footer of your emails. If you don't have an actual office or are working from home, use any address where you can receive physical mail from clients.

Tip #17: Add an unsubscribe link to each newsletter email


image courtesy of reallygoodemails

Subscribers will come and go, and it's not always because of you. So do not try to make the unsubscribe process as difficult as possible to keep them subscribed. Let them unsubscribe from your mailings easily. If you don’t provide them this option, they may find it easier to click the "This is spam" button, and this is no good for you, because spam complaints hurt your deliverability, unsubscribes don't.

Tip #18: Check your newsletter sending frequency

Sending too many emails can make your recipients stop opening them. On the other hand, when you send too few messages, people tend to forget you. To find the right balance, try to create different test groups and send your newsletters at different frequencies. Then analyze which frequency generates the best opening and click-through rates and stick to this frequency.


If a person has a poor reputation, then they unlikely will be invited to a wedding or a baby shower. The same goes for electronic messages: emails with a bad reputation are being marked as spam or just lost at all. To avoid email going to spam, be sure to:

  • Know the laws regarding email spam (CAN-SPAM, GDPR, CASL, etc.);
  • Ask permission to send messages (the double opt-in method);
  • Use only reputable email marketing service providers like MailChimp, Aweber, Active Campaign, Infusionsoft, ConvertKit;
  • Optimize your content (write a good subject line, strive for a right balance of text to image ratio, don’t use words that trigger spam filters, find a reliable image hosting site, be short and concise);
  • Send only to subscribed users;
  • Clean up your mailing lists regularly;
  • Use email spam checkers;
  • Test and analyze.

What are your tips to prevent email from going to spam? We are keen to learn from your experience.


Contact with me


CMO at Newoldstamp at Newoldstamp

Helga is a growth marketer with 7+ years of experience. Since 2015 Helga has switched to SaaS market. Prior to joining NEWODLSTAMP she successfully cooperated with several SaaS companies that provide top-notch solutions for marketers.

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