7 Effective Ways to Improve Email Deliverability


email deliverability email marketing

Are you frustrated when all your marketing effort ends up in a junk mail folder/spam folder? We know that troubles you, and that’s why we’re pleased to guide you on how to optimize your email campaign and make it to your subscribers’ inbox. Let us share with you 7 effective ways to improve your email deliverability.


What is Email Deliverability?

Email deliverability means the ability to deliver emails (including bulk emails) to subscribers’ inbox. It is a metric used to measure the likelihood of our email campaigns reaching your subscribers’ inbox related to actual delivery, such as ESPs, open rate, bounces and spam issues.


Understanding the email service providers or ESPs

To make sure your Email Deliverability is always at a tip top condition, you must first understand how Email service providers or ESPs work. Some of the major email service providers are:

  • Gmail
  • Hotmail
  • Yahoo mail
  • Other smaller ESPs
  • Self-hosted emails

These ESPs can be categorized into 2 groups based on the spam filter protection level, namely low and high. Hotmail is the only ESP that has the highest level of spam protection and is being categorized as group 1 by itself. Other ESPs such as Gmail and Yahoo mail have slightly lower spam protection levels and are categorized as group 2. Self-hosted emails vary based on the spam filter software they are using.

Since Hotmail, Gmail and Yahoo Mail are the top three ESPs on the market, in this blog post, we shall focus on them.


Important Metrics in Email Marketing

Open Rates

The Open Rate is a metric that measures the rate of every email campaign at which emails are opened. Open rate is a very important metric that determines how well your email campaign performs. It also determines the deliverability of your email campaign. The following are the suggested benchmark of open rates:

  • Below 5% – it’s very problematic
  • Between 5% & 10% – it’s very average
  • Between 10% & 20% – it’s good
  • Above 20% – it’s considered very good
Click Rates

The click rate is a percentage rate that tells you how many emails successfully get one click from a recipient. It is usually used to determine how good your email content is when it comes to attracting the recipient to click your link to find out more. A good click rate is more than 10%.

Unsubscribe rates

The unsubscribe rate is a metric that indicates the percentage of recipients who have opted-out from the mailing list (do not want to receive your emails anymore) after an email campaign. It is advisable to keep the unsubscribe rate below 1%


Email Technical Keywords:

Some technical keywords that you might encounter when setting up your email marketing campaigns:


Used to prevent identity theft. Add in your DNS zone the list of IP authorized to send email with your domain name.


Used to verify that the message has not been altered. Insert a digital signature to sign to your message. The ISP will verify this signature with an encrypted key located in your DNS records.


Act as the third option in case of SPF & DKIM authentication failure. Indicate to the ISP what to do in case of an authentication failure. Allow the sender to be notified when authentication fails.


Email deliverability: How to send your emails right into your audience’s inbox

1. Check Your Contact List

If possible, separate Hotmail contacts from those hosted with other email service providers. Hotmail is relatively sensitive when it comes to spam filters. Some research statistics show that 2 to 3 consecutive emails with “No Open” will cause your next email to reach the spam folder. Hence, we should handle Hotmail clients with more caution.

Make sure your contact list is obtained through self-willingness signup. Some businesses send mass emails to a list that is obtained either from existing customer lists or from offline email collections. These contacts actually do not provide the right for you to send emails to them.


2. Send High Quality Content

Content is king. Make sure you have a high open rate and click rate. ESP’s main focus is to provide the best email experience to their users. If you provide high quality emails that users are willing to open and engage with, your email deliverability will be good!

So what is defined as good content?

Good content is content that is able to create engagement — catchy headlines, beautiful designs, easy to read, interesting and well structured content etc. All these are contents that will get engagement from the users. In other words, the metrics that we mentioned above (open rates, click rates and unsubscribe rates) should be at least satisfactory.

Besides, using a content modifier that will help address users’ names inside the email can also help boost the engagement of that particular email. This makes the email look crafted/ personalized to the particular recipients only.

However, there are content and keywords that you should avoid in your email so that the spam filter will not be triggered to send your email to the junk mail folder. Below are some of the content that you should avoid, especially in your subject line.

  • Avoid “promotion” “sale” “offer” or other related keywords
  • Avoid promotion text like “50% OFF”
  • Avoid making money related keywords: “Extra Cash” “Earn Cash” “Make Money”
  • Avoid the word: “Free”
  • Avoid all caps, exclamation points and the use of red fonts
  • Use reliable email service providers with good IP reputation


3. Email IP Address

Every email is sent from a specific server that has a specific location or online address. This address is called an IP address. Your Email IP Address plays an important role for email service providers (ESP) to determine whether to send your emails to the inbox or not. There are 2 types of IP Address for email:

Shared IP – IP that is shared among several users
Dedicated IP – IP that is used by one specific user only

If you wish to get the best results for your email marketing campaigns, it’s highly recommended to choose a dedicated IP. Using a dedicated IP ensures that your performance and reputation is not shared by others.

With a Dedicated IP, you have full control on your IP, including maintaining and controlling your own IP reputation to make it “welcome” by email service providers.

Below are some of the ways to maintain or enhance your IP reputation:

For Gmail, yahoo mail and other ESPs, we recommend you to perform an IP warm up, which is a slow increase in the number of emails sent out every time. You can send it out with a 30% increase. This is to warm up and slowly let the ESP recognise and accept your IP address.

For Hotmail, you must have a different approach. You should have a list of Hotmail subscribers first and perform the warm up process with a much slower scale. This is because when it comes to Spam Filter, Hotmail is more sensitive compared to others.

*Note: This warm up method is only applicable for dedicated email IPs.

Some email marketing software do not provide such tools for you to warm up your IP. In this regard, Exabytes EBuzzzz email marketing does provide such function for you to warm up. Just fill in the number of emails you wish to send each time and the percentage you wish to increase for the next send, and you are good to go. It’s just that simple.

4. Separate Send Based on Email Types

We should also send emails based on the types of emails. There are 2 main types of emails, namely Marketing Emails and Transactional Emails. They are the 2 different types of emails that should not mix together when using bulk email sending. Let’s have a look at the differences between them.


Transactional Emails

Transactional emails are emails that are used to send important info such as invoices, passwords, account details etc.

Marketing Emails

Marketing emails on the other hand, are emails that send promotional and sales related info.


It is advisable to send these 2 types of email separately using different email IP. This is because IPs that send marketing emails might get penalized by ESP. ESP do not like promotional emails, they take it as spam and will try to send these emails into the spam box. If we use the same IP for these 2 types of emails, it can affect the deliverability of transactional emails. As we know, sending transactional emails is very important to a business and we should try to keep the IP clean and free of promotional items so that transactional emails can go into the recipient’s inbox.

Hence, it is advisable to use an dedicated IP for your transactional email to ensure important emails are sent to recipients.


5. Bounce Emails

Email bounce can cause your IP reputation to drop and is one of the important aspects that you must take care of in email marketing. Generally, there are 2 types of email bounce, namely soft bounce and hard bounce.


Soft Bounce

A soft bounce happens when an email is able to get into the recipient’s mail server but is bounced back undelivered before it gets to the intended recipient’s inbox. A soft bounce might occur because the recipient’s inbox is full. It’s recommended to maintain the soft bounce rate below 2%.

Hard Bounce

A hard bounce email indicates a permanent reason an email cannot be delivered such as invalid email, email no longer exists, etc. It’s recommended to maintain the hard bounce rate below 1%.


In order to maintain your email deliverability and protect the reputation of your IP address, you should make sure these bounce numbers are always low. To keep them low, after every email sent, have a check on the bounce rate generated and remove Hard Bounce emails from your sending list.

Make sure you choose a good email marketing service provider, such as Exabytes EBuzzzz Email Marketing that is able to provide you with insights on your bounce rate.


6. Manage Blacklists

There are different entities that determine your IP’s reputation. We will share with you some of the realtime databases that determine whether or not your IP is sending spam emails.

Basically, there are 3 main blacklists:

  1. Spamcop
  2. Spamhaus
  3. Cloudmark


Go to these websites and check your IP to find out if it is blacklisted or not. Checking is simple, just type in your email IP address or your website domain name, and you’ll find out if your IP is blacklisted.


7. Test your emails before send

You can actually test your email every time before you send out. Go to mail-tester.com to test your emails. The steps are very simple, just send your email to this website (a special mailbox is provided) and you will get a score and a detailed statistics, analysing which part of your email should be improved.

This tool is free to use and we strongly recommend that you take this test before sending out your emails.

The Bottom Line

In conclusion, the key to improve email deliverability is by “sending the right email to the right person at the right time”. Focus on delivering the best content to your recipients and you are on your way to enjoy good email deliverability.