Email Deliverability: A Guide To Keeping Your Emails Out Of Spam

September 30, 2021

Your emails must make it into the inbox to be effective - regardless of whether they are transactional emails like password resets or marketing emails such as newsletters and promotions. But sometimes email deliverability becomes a consistent cause of headache for email marketers.

email delivered to inbox graphic
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Your email marketing campaigns need to reach inboxes, instead of spam boxes, to get any ROI from them. In this beginner’s guide to email deliverability, we will show you everything you need to know to increase your deliverability.

Table of Contents


  • Email deliverability is the ability to successfully deliver an email to the inbox of a recipient.
  • The delivery of emails can be affected by many factors including Internet Service Providers (ISPs), bounces, and spam.
  • The principle of email deliverability is a straightforward one: Ensure that you send emails only to people who want them and when they want them, with the content recipients want.
  • The elements that contribute to email deliverability are Authentication, Reputation, Content, Infrastructure.
  • It is more important to focus on the recipients than on the growth of your list to reap repeated long-term rewards.
  • It is crucial to create valuable and personalized content to entice your recipients to open your emails.

What Is Email Deliverability?

The planning, draft, and experimentation of an advertising campaign take time, effort, and determination. Marketing teams build emails from scratch or modify templates to ensure superior success with email campaigns.

It can be devastating to learn that your emails did not reach your subscribers after putting so much effort into them. The average percentage of undelivered emails is 20.4% based on data from February 2020, rising from 16.3% in July 2019.

Despite how well executed a strategy and how well planned an email design may be, ROI will not be achieved if the email does not reach the inbox. Ultimately, everything depends on email deliverability.

Email deliverability refers to how many emails reach subscribers' inboxes without any problems. The ability to reach targeted inboxes is an essential metric of business success because emails that reach targeted recipients are more likely to be opened. Effective email campaigns require strong email deliverability.

It is important to remember that the email inbox placement does not indicate email deliverability. Deliverability is defined as the percentage of emails that have been neither rejected nor bounced.

Basic Email Deliverability Guidelines

Always Use Double-opt-in Confirmation When Sending Out Emails

Generally, this requires the user to confirm that he has signed up for your email list. You should send an email to registered users and subscribers to your email newsletter only when they subscribe. Upon receiving the email, the subscriber will be asked to click on a link to confirm that he owns the email address and wishes to receive emails from you.

Set Up Separate Email Accounts for Each Type of Email

Your company may wish to send Transactional Emails along with Newsletters, Receipts, Reminders, etc. Use a domain and IP address that is separate for each type.

Use "" for corporate transactions, and "" for all other emails. There should be a dedicated IP for each domain.

It is common for Google and other ISPs to combine/group your corporate emails under the "Promotional" and "Other" tabs when they receive incoming mail mixed with other types.

Register Using the reCAPTCHA Provided by Google

A reCAPTCHA is a feature offered by Google that prevents automated bots from reading your site, registering, and subscribing. You may harm your emailing metrics by sending emails to bot registrations or to people who exist but have been registered by a bot.

A bot registration email sent to an ISP that is never opened and/or clicked through indicates that ISP that not too many people are interested in your email and that your email can be treated as junk/spam.

Make Sure Emails are Verified on Registrations and Sign-ups Using a Real-time API

The previous step discussed how bots can sign up real people. If you send emails to people who have not confirmed to receive them from you, your email may be marked as spam, which will result in decreased inbox rates.

Email Deliverability: Costs and Benefits

Good Email Deliverability Brings Benefits

  • Inboxes will be filled with more emails to read and open.
  • Your customers will receive the latest news and content.
  • Customers will receive important transactional messages as shipping notifications and password resets.
  • You will not have to worry about spam.
  • Your email marketing efforts will be more effective due to the increase in ROI.
  • Visibility in the inbox can give you the edge over your competition.
  • The recipients of your content will be more engaged with your content.
  • Analyze performance metrics such as open, click-through, complaints, and ROI to enhance marketing performance.

Poor Email Deliverability Brings High Costs

  • The emails will not reach the inbox or be read.
  • Customers will not be notified of the important and latest news.
  • Important transactional messages such as shipping notifications and password resets can be overlooked by customers.
  • Email marketing will become less effective because of a decrease in email ROI.
  • Competitive companies with good deliverability gain a higher rank in the inbox.
  • There will be a decline in engagement and responsiveness from your list going forward.
  • The failure to track performance metrics such as open rates, click-throughs, complaints, and ROI.

Which Elements Contribute Greatly To Email Deliverability?


Email is a great method of communicating, but how do the recipients know you are the person you claim to be?

In today's world, scams, phishing, and spoofing are so common that recipients aren't able to discover the sender's identity or other details beyond the sender's name and address.

It is necessary to use email authentication protocols to prevent fake mail from reaching email providers. The protocol that verifies who you are when you send an email includes Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and the Domain-Based Message Authentication, Reporting, and Conformance (DMARC).


The reputation of a sender indicates the trustworthiness of an email. The amount is determined by blacklist listings, bounce rates, complaints, and email volume. The importance of your reputation may be affected by several factors, depending on your customer base and Internet service provider (ISP).

However, generating positive subscriber feedback (i.e. users marking you as trustworthy senders) is one of the most effective ways to improve it.

It takes time to build a good reputation, and it is easy to damage it. Your message will be delivered directly to the recipient's inbox if you have an excellent sender reputation. Additionally, if you have a poor reputation as a sender, your emails may be sent to junk folders or rejected at the gateway.

email deliverability process

Here are some ways to maintain a good reputation as a sender:

  • Maintain a clean mailing list to reduce bounce rates.
  • Utilize trustworthy and reliable servers such as VerifyBee to ensure low abuse complaint rates and better delivery.
  • Stay off blacklists.
  • Don't fall victim to spam traps.
  • Communicate frequently with subscribers and adapt emails to their preferences.

Maintaining good relationships with ISPs is essential for email marketers. A good reputation will indicate that you are sending emails to people who are interested in receiving your emails.


Email delivery is extremely dependent on the quality of the content you send. The ISP's continually monitor and filter spammy, phishing, and questionable emails for their subscribers. Thus, to gain their support, it is important to write and design emails with a quality focus.

When you write your emails, keep your customer's perspective in mind. Here are some tips you may find useful:

  • Keep external links to a minimum. In your emails, the rule of thumb is to link to your website. Due to the nature of this fraud technique, spam and phishing filters will flag excessive external links.
  • Be sure to add text to your emails. It's a good idea not to send e-mails containing only images. Many phishing emails use only images, so spam filters may mark them as spam.
  • Make sure your emails resonate with your recipients by personalizing them and adding product recommendations.
  • Relevant and valuable content is necessary to maintain subscribers' interest.


Your email infrastructure is made up of all the hardware and software required to deliver emails. All of this is handled by email marketing services.

Infrastructure has a significant impact on email delivery, for example:

  • Sending Domain
  • IP address
  • Click Tracking

Developing and maintaining your email marketing infrastructure can be quite a difficult process. Email services can handle the marketing process in an efficient manner, which is why we recommend they be used for the entire operation.

How To Ensure High Email Deliverability

List the Right People

Ideally, your target audience wants to receive your email, consents to receive it, and is expecting it from you. Ensure your mailing list is targeted to a specific segment of your target market, and it contains accurate and current contact information. The audience on this list is generally one you've built over time.

Use only your own list. Never buy, harvest or scrape a list of any kind. Establish direct relationships with all of your addresses. Make sure all new signups are confirmed via double opt-in. Rather than automatically signing up people for your mailing list, ask them if they want to be on it. Provide clarity in your signup process, including what a person is signing up for, when they will start receiving emails, and how often you plan to contact them.

Create Great Content

The content for a marketing campaign must be well-written, compelling, and valuable to the recipient for it to succeed. It's your job to know your audience; share content that keeps them engaged through content they will want to read.

Good email content engages and informs the reader above all else. Create such content that motivates the recipients to open it. The use of a short, intriguing subject line or familiar term will grab their attention and give a clear picture of what the email is about.

Personalization is Key

The evolution of email marketing has given marketers more power than ever before to send targeted, personally tailored, and even dynamic emails to their list members.

Whether you measure campaign results as open rates, click-through rates, or even revenue generation, the more targeted and specific your message is for your recipients, the better your campaign will do.

The more specific the message is, the greater are the chances that the recipient will open and read it. A significant factor driving conversion rates with interactive marketing is the personalization of content. For example, "Hey Allie" would be a much more straightforward and personal greeting than "Hello Customers,".

personalized email by sephora

Monitor Your Open Rates, Clicks, and Bounces

A successful email marketing plan entails adjusting your audience and your content over time to achieve the best results. This requires tracking all aspects of your campaign, including whether your messages are delivered, opened, clicked, forwarded, or if they have been acted upon.

It is always wise to compare different campaigns across the board, especially when testing several messages simultaneously.

As you compare the results of each campaign, you will be able to discover trends in your content and the behavior of your list that could lead to better-tailored future content and messaging.

Segment Your List

While it might seem like a good idea to build one list and email them all with the same message, segmenting that list offers superior marketing value.

In a nutshell, segmenting is using established criteria to create smaller lists by taking one large list and turning it into several smaller ones.

The criteria might include demographic information (age, gender, education, and so forth) or could include browsing behaviors, memberships, or other data, such as pages visited on your website, what links they clicked, and so forth.

Once you have a large list of information like this, it's easy to sort subscribers by categories. While you can still send a single email to the whole list when deemed appropriate, you also have the option to send a targeted email.

Keep a Clean List

Getting a clean list is key to a good email marketing solution. In addition to removing nonexistent domains and invalid recipients, it will remove users who have opted out of receiving future emails or who complain.

While email marketing platforms do not have list-cleaning tools, keeping your list clean is your responsibility. You should start with a valid, properly qualified list of recipients. Your email marketing platform can help automate some of the ongoing list maintenance while you send emails and build your sender reputation.

Cleaning email lists manually can be time-consuming and at times impossible. An email verification service like VerifyBee can help you verify your emails and phone numbers quite easily. You can do it by connecting to your existing CRM, or simply uploading a list.

verifybee email verification homepage

The Bottom Line

Email deliverability may seem difficult, but if you follow a few simple guidelines, you can increase its success rate significantly. Make sure to establish email authentication protocols, create engaging content, and stay away from blacklists to avoid spam filters and blacklisting.

The use of email verification is one of the most effective methods. To ensure quality data collection, first, verify email addresses. Verifying email addresses can help you improve your email marketing, fraud prevention, and sender reputation.

Want your email list to be verified in real-time? Get started with VerifyBee for free today and boost your email deliverability in no time!

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