Email Deliverability practices to avoid the spam filter
Written by
Ninad Pathak
Ninad Pathak

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Email Deliverability practices to avoid the spam filter

Published : June 24, 2019

Data is the new oil, and those involved in running online email campaigns would know the intricacies involved in collecting it — especially email IDs, which is classified as personal information. Currently, the ISP algorithms and data privacy laws such as General Data Protection Regulation (GDPR) make bulk emailing extremely difficult. So many times, legitimately relevant data can be marked as spam by these filters due to noncompliance with regulatory laws.

So, digital marketers and businesses are compelled to obtain the user’s consent before shooting an email. Now, this is exactly where the trouble begins, so let us start from data collection, and then move on towards other measures that help prevent emails from being marked as spam


1. Collect Data Legitimately

With the fast-changing data privacy laws and ISP algorithms, buying email lists could be a felony as well as a blunder. So gone are the days when you could count on the dark web to sell you databases. Currently, you need to invest time and money in drawing the attention of your target audiences, before you blast out emails.

So, it is recommended that one invests in landing pages, online advertising, and social media, to legitimately collect email IDs. Experts recommend a two-step opt-in to be on the safer side. Once that is done, the next biggest hurdle that you need to overcome is to ensure that your email finds its way into the inbox of your target audience

 2. Using SSL Certificates for secure communication

Using an SSL Certificate on your email server can help enhance your credibility by providing end-to-end encryption, which makes the process secure and helps improve your email reputation. Secure Socket Layer (SSL) certificates naming SMIME certificate that encrypts the data passed on from the client to the server, so when you make use of an SSL Certificate, it adds credibility to your emails. You can get an SSL certificate from reputed SSL resellers or direct from certificate authorities like Comodo, Symantec, GlobalSign, etc.

Although presently SSL Certificates are succeeded by Transport Layer Security (TLS), the two acronyms are used interchangeably, so TLS Certificate is often dubbed as SSL Certificate. The fact that there are very minor technical differences between the two only contributes towards the use of this misnomer

 3. Getting through the Gatekeeper

Navigating your way through the ISP Algorithm and other filters— which we collectively refer to as the gatekeeper, can be quite a challenge. As technologies continue to vigilantly guard inboxes, suspicious emails go straight to the spam folder. After all, IT Giants like Microsoft, Google, etc… are doing all that they can, in order to provide their email users with the best user experience. However, since it is an automated system that is doing the gatekeeping, you can easily figure out the roadblocks and eliminate them. So, there are certain specific norms that the algorithm follows in order to detect anomalies, and you need to nail those.

The first thing that you need to have in place is the SSL Certificate, and then you must design content that gets through the ISP algorithm. You must avoid spam trigger words like discount, free, sale, etc… which most digital marketers tend to use in the subject line to grab the attention of the reader. Also, you need to avoid using deceptive, misleading, and false subject lines

 4. Exchange Server Security

When it is a question of Exchange server security, SSL certificate cannot be avoided as it encrypts the communication between internal servers and exchange services on local server. Exchange admins need Exchange Server SSL certificate for internal and external clients as well external messaging servers to secure their communication. A digital certificate can be assigned to outlook on the web, outlook MAPI and HTTP, exchange web services, Autodiscover, Exchange ActiveSync, etc. SSL certificate on exchange servers serves different purposes like Secure Internet Mail Extensions (S/MIME), IPsec

 5. Clean up your database regularly

You need to update your email lists periodically, to eliminate those who aren’t interested in your product or service. This means you need to get rid of the subscribers that have unsubscribed from your emails or have probably marked you spam. That helps prevent the emails from bouncing back, which could potentially damage your email reputation. A point to note is that when there are too many bounce backs, the ISP presumes that you are a spammer and sends your emails to the spam folder

It doesn’t matter how many people you blast out an email to, rather what does matter is that you reach out to those who are interested in your product or service. So, if someone isn’t, then you can make it easier for them by providing an opt-out link. Always make sure that your emails have an opt-out link, which you can do by using an ESP. That means you need to avoid asking the Reader to email back to you, in order to unsubscribe, because if you did that then this simple mistake could further damage your email reputation

 7. Carefully choose your ESP

Email Service Providers (ESPs) provide you with a shared IP Address, which is likely to be shared by you and others — people, you have no control over. So, if they fail to comply with the best email practices, then the email reputation of everyone using that IP is likely to suffer a blow. This happens because email reputation is associated with the IP address which you are probably sharing with others. To avoid these issues, it is recommended that you consider a dedicated ESP IP Address.

 8. Email Testing

Finally, when you are all set to launch your email campaign, there’s one last step that you need to go through — email testing. This step provides you with insights about the performance of your email campaigns on different platforms. You can also use testing tools like A/B testing to compare two versions of the same email, or even compare the response generated by different logos in case of rebranding.

It also helps you to get a clue of how your emails are going to look on different devices through the screenshots provided by the email testing service providers. You can also use email testing to identify elements that adversely impact your email campaign, making it appear as spam. Not to mention, email testing can greatly help improve your click-through rate.


The present e-commerce market is much more data-driven than ever before. Hence, to run a successful email campaign, one needs to niche down and trigger the interest of the target audience. So, the content in the email needs to provide value to a very specific set of users, who want to receive emails from you — something that’s best done with a two-step opt-in. As a matter of fact, it does not matter how many people you reach out to, instead what does matter is the click-through rate that your email campaign achieves.

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Written By: Ninad Pathak