convesio logo

Email Marketer’s guide to avoid the spam folder


In this Article

This blog post is from the archived blog. In 2024, Convesio acquired Growmatik and re-launched it as ConvesioConvert. Learn more about ConvesioConvert.

Email marketing is one of the earliest and probably the most everlasting marketing channels in the digital era. It definitely had its own fluctuations and evolution but despite the predictions of its demise in different periods such as the social networks era, it has survived as a relevant marketing channel up to this day. In fact, many believe email marketing is the most effective marketing channel far ahead of websites, social media and PPC.

Email marketing, however, has undergone massive evolution in its lifetime. Many new tools and standards have emerged that have overhauled the face of email marketing in the last decade. You cannot compare today’s email campaign to those of the early 2000s. What was simply considered a promotional email that was sure to be opened by the recipient then may not even sit in a user’s inbox today as email providers and services have developed many new quality measures to ensure their users receive the most relevant emails and fewer spam.

This in fact may be the reason that email marketing is still a thing in digital marketing as it has helped this marketing channel be relevant in a market where the likes of Google and Facebook are in fierce competition to deliver the most targeted and relevant ads to their users. In this article, we’ll review all the standards you should strive to meet if you want your email campaigns to avoid the spam folder and end up in your target recipient’s inbox.

We already explained how to send engaging emails to increase conversion, and in this article we will focus on everything you should do to maximize the delivery of your emails and how to avoid emails going to spam.

The only way to avoid the spam folder is Relevancy

You’ve probably always heard this from SEO veterans: the best SEO strategy is to build  high-quality relevant content. This holds true for email marketing as well.  If you want to make sure your emails are not rejected or delivered in spam folders, opened and clicked on, your goal should really only be to send relevant content to relevant people. Because that’s the only thing email provider services care about: ensuring their users read the most relevant emails.

The best SEO strategy is to build relevant content, and the best email deliverability strategy is to send relevant emails.

But when email providers inspect the relevancy of your email to their users, they don’t begin by looking at the content of your email. They inspect other various factors prior to the content before deciding if they want to accept the email and then which folder to put the email in (primary inbox, promotional inbox, spam, etc.). Below let’s have a look at these factors in detail.

Using your own domain to send emails

Use your own domain when sending marketing emails to your subscribers. If you want to avoid the spam folder, using free email providers such as Mailchimp might be risky as you may be affected by the general reputation of those email providers in the eyes of ISP (in email marketing, ISP or ESP refers to the major email providers: Gmail, AOL, Outlook, Yahoo, and so on)  For example, if another Mailchimp user abuses Mailchimp to send low-quality emails, Mailchimp’s general score will be affected in the eyes of Gmail, and you’ll be get affected by that poor reputation as well. Furthermore, if your users have a history of interacting with other emails you’ve sent (for example transactional emails), then there will be a much higher chance that the ISP will  put you into the recipient’s primary inbox as they have interacted with you once or multiple times before.

Some of the email marketing tools offer email white-labeling features. You can refer to this documentation to learn more. For example, in Growmatik you can add custom outbound address in the site settings and use them in different email campaigns.

avoiding the spam folder

Properly implement your authentication records

Authentication records are the first thing your recipient’s ISP will check to decide whether to deliver your email to the inbox or filter it as spam. The two main protocols your email server should support are DKIM and SPF.

SPF (Sender ID)

SPF – also known as Sender Policy Framework – allows the ISP to authenticate a sender’s identity. By discerning YOU as the sender and no one else, SPF helps hinder someone else from sending out emails with your name and boosts the rate at which your emails will be delivered.


DKIM, which is known as Domain Keys Identified Mail, is the sender’s coded authentication message that links the email to the server’s DNS of origin and verifies to the receiver that the domain is real. In this way, the emails that you send out have a  type of identification, which also helps to avoid the spam folder and enhance the delivery rate of your emails.

Authentication records are pieces of code included in your email header section and function as a digital signature helping to verify your identity and eventually increase your campaign’s delivery rate.

avoiding the spam folder

These records are critical if you are using an email automation platform as it authorizes those platforms’ servers to send emails under your name and with your own domain. So you should make sure the platform you use provides email white-labeling features and supports these protocols. For example, in Growamtik, once the custom outbound addresses are added and verified by the tenant, the DKIM and SPF records are automatically added to your email header.

Send more transactional and less broadcast

There are two types of marketing emails: transactional and promotional (or broadcast). Transactional emails are a result of a specific action that the recipient has made while interacting with your business. For example, the welcome email you send your lead after they sign up to your blog or the confirmation email you send to your customer after they place an order.

Broadcast Email Transactional Email
Newsletters Abandoned cart messages
Product promotions Order notifications
Invitations and announcements Account creation & password reset

Your users will expect transactional emails, so the recipient’s ISP marks it as highly relevant and gives it a good quality score. On the other hand, promotional emails are mass promotional campaigns sent to everyone in your leads or customers list. These emails are less personalized and more likely to get marked as spam or sit in the promotional emails tab.

Your recipient’s ISPs look at various attributes from information contained in the email header and content before it makes a decision about whether to accept or reject your email and whether to put your email in the primary inbox, promotional inbox or spam folder. The best practice to avoid the spam folder or promotional email triggers is to send emails that are a combination of both transactional and broadcast approaches.

avoiding the spam folder

The best way to do this is by personalizing your promotional emails. And by personalizing, I don’t mean just adding the name of the user to the subject and beginning of the email. An email automation tool like Growmatik provides many dynamic keywords to personalize the body text by personal attributes related to the user’s in-site and shopping activity.

In addition to body textual content, the item(s) you promote should be different from recipient to recipient and based on their actual shopping behavior. Cross-selling emails are a good example of personalized promotional emails. In Growmatik, you can use the Product Element in the email builder to insert personalized product lists related to recipients’ recent or overall shopping behavior inside the email.

Check your email sender reputation

The Email Sender Reputation is basically a score that is assigned by an ISP to a company or organization that sends emails. One of the first things that an email provider checks when they receive a request to accept an email is the sender domain and its reputation.

If your sending domain has a poor record in the eyes of the email service provider – for instance, many spam reports from their users – it will dramatically affect the quality score of your email and hence be rejected or end up in the spam folder. It’s good practice to regularly check the reputation of your sending domain and take action when the status is low and beginning to drop. There are many free tools such as Sender Score, Barracuda Central, Thalos database, MXToolbox and Google Post Master and Mail Tester that provide your sender score as well as tips on how to improve it.

Each ISP has its own criteria and measures to determine and score quality scores to emails but the majority have the following in common:

  • The number of emails sent by the organization
  • How many recipients mark the organization’s emails as spam or 
  • How many recipients complain about the messages
  • How often the organization’s emails are caught by the ISP’s spam trap
  • The organization’s inclusion on reputation databases such as 
  • Number of recipients open, reply to, forward, delete and clicks the organization’s email get 
  • Number of unsubscribes from the organization’s email list

Comply with CAN-SPAM and GDPR in broadcast emails

Certain regulations exist online that further empower the users to see the type of content that they want to see. The CAN-SPAM Act applies to commercial emails and sets out requirements for messages, provides recipients with the right to stop unwanted emails and establishes harsh penalties for anyone who violates the regulation. Furthermore, the GDPR is a set of rules to give EU citizens more control over their personal data.

CAN-SPAM and GDPR rules are important anti-spam requirements for your broadcast campaigns to avoid the spam folder and also to avoid violating the law and getting penalized.  Here are the main highlights:

  • Provide clear and explicit consent given by your recipients to send them emails
  • Use emails only to the extent of recipients consent 
  • Provide accurate header information
  • Provide honest subject lines
  • Provide your legal location
  • Provide a way to opt-out 
  • Proceed with opt-out requests quickly

The first step to make sure your broadcast email campaigns comply with these rules is to check if your email marketing platform is compatible with these two protocols. You can do this by using a compatible tool that implements the above objectives natively in its lead generation forms, email builder and email sending mechanism. Below, we’ll learn more about these objectives.

Add address and unsubscribe options in broadcast emails

A GDPR and CAN-SPAM compatible tool will force you to include your legal physical address in every broadcast email’s footer. For example, the Growmatik email builder will automatically place the address module in your email footer.

Include quality content in your emails

Your recipient’s ISP is following a sophisticated algorithm to understand and judge your content before it decides which folder it should go to.

Content should match the consent given

If your recipient is a user or customer and needs to be notified about certain things, send them only the transactional emails that they expect to receive. Send broadcast emails only if your recipient has allowed you to send them marketing emails.

Comply with CAN-SPAM and your sender’s content policy

Your email content should fully match with CAN-SPAM content guidelines and that of your email marketing platform (e.g. pornography, phishing, cyberbullying,…)

Avoid HTML content where possible

If you are sending an HTML email, there is no chance of your email landing in the primary folder. Majority of ISPs’ algorithms mark HTML content as broadcast emails and move it to the promotional tab.

Plain text with minimal links and images give the highest chances of being delivered to the primary inbox.

Use a decent Image/text ratio

Your email content should represent a decent image/text ratio. No image content is more likely to go to the primary inbox (given other criteria is met), and image/text content will likely go to the promotional tab. No-text content is very likely to go to the spam folder.

Mind the language!

If you don’t want to be marked as promotional, avoid using notorious marketing terms both in your subject and body such as discount, sales, action, apply now, call now, unbelievable (and of course viagra!).

Use links consistent with your From address

If you’re including a call-to-action in your email, it’s better to link it to the same domain as the From address stated in the email header. Otherwise, the recipient ISP may think you’re an affiliate marketer who is trying to sell something for affiliate earning for another brand or service.

Use double-opt in sign up forms

Double-opt in has always been one of the most important measures to build and maintain a healthy mailing list. This is especially important when you’re trying to create a list for broadcast emails. Double opt-in not only helps to have a healthy and engaging list and helps to prevent wasted costs but also is dramatically effective in maintaining a good domain sender score. For example, some of your subscribers may have left a typo when they entered their emails in your subscription field and when you send an email to that address, the ISP will reject the email and you’ll get a negative score for your domain. This can be prevented by a double-opt in signup form.

Monitoring campaign performance and sending reputation

This is the last step and probably the only step that should recurrently happen. After doing all the above and start sending your campaigns, you should check each campaign’s performance analytics and also your general domain’s sending reputation in an organized manner. For campaign performance, you should check your email marketing platform analytics.

avoiding the spam folder

For example, in Growmatik, you can check the performance status of an email campaign by checking the Report section in the automation dashboard. To monitor overall sender reputation over time, you can use tools like Mail Tester.

Keeping an eye on your email campaigns status will help you notice problems – for example,  low engagement or delivery rates – before it’s too late, fix the problem and help to avoid the spam folder in the rest of your campaign.

In this Article

Convesio Hosting Dashboard
Related Articles
Get WordPress Performance Tips
Subscribe to our monthly newsletter covering performance, innovation & running WordPress at scale.