Listen Email Deliverability Guide – 23 Minutes

Imagine spending hours trying to send out emails that get deposited into a junk folder. Is my email deposited into my customer junk folder? This article reviews email deliverability and shows ways to improve both sender reputation and avoid spam. Let’s start with facts.

This email deliverability guide will provide exact information regarding having a higher sender reputation and better email deliverability. We will start with general information about how a sender’s reputation can affect your email deliverability and how you can avoid all the mistakes and avoid spam traps. You will reach the best of your email marketing program.

Here are the main subject lines we will discuss in this article.

  1. Keeping your sender reputation high.
  2. Email Server IP Address Quality.
  3. Verify and clean your email list for invalid, spam traps, and temporary fake email addresses. Get rid of inactive subscribers.
  4. Email service providers and choosing an email marketing service.
  5. Dedicated ip address vs shared ip address.
  6. Total sender policy framework.
  7. Increase your email deliverability with the best practices.
  8. Have higher email campaign open rate and generate more sale.
  9. No more spam complaints. Don’t become one of the malicious senders.

Let’s start!

Email Sender Reputation Explained
Email Sender Reputation Explained

What Determines Sender Reputation?

Before we begin, you should note that it is normal to fluctuate from ‘average’ to ‘excellent’ reputations. It could hurt your reputation for sending an email to an audience that is not engaging. Having more engaged customer emails improve the business sender’s reputation.

The sender’s reputation comprises two elements: IP reputation and the percentage of the marketing emails reaching to recipient’s inbox, email deliverability, or inbox placement. The two variables have different effects on delivery quality, but they both significantly influence the quality of email deliverability.

Even though both email deliverability and IP reputation affect each other’s sender score, we need to evaluate both in different parts.

Why is IP address quality important for email deliverability and sender reputation?

Ip address is the internet ID assigned to your SMTP server (simple mail transfer protocol – email sender server). All your marketing emails get delivered through this IP address. When any email service provider (i.e., Gmail, Hotmail, etc.) receives an email from your domain address, they value three things in the hierarchy below:

  1. Your IP Address
    1. Your Domain
      1. Your Email Address

Think of this as Pavlov’s triangle.

Email Deliverability Triangle by Midjourney
Email Deliverability Triangle by Midjourney

At the top, your IP address stands. The Ip address covers everything about your reputation.

Next, the domain address of your business is essential.

Below the domain address of your business, you have your email addresses. You might have multiple email addresses (employee emails, support, no-reply, contact, etc.) under this domain address.

Here is a short and straightforward explanation of IP addresses, domain addresses, and email addresses. We will explain in depth why each of them is important and what steps need to take for high email deliverability and to keep your sender reputation high.

IP reputation
IP reputation

IP Addresses

Email servers need an IP address provided by internet service providers or data centers. Your email server gets hosted at these providers, and your email clients connect to this IP address when sending emails. These hosted servers deliver your emails over the IP address.

Domain reputation
Domain reputation

Domain Address

The domain address is associated with your business when sending an email. For example, in this email address example,, the domain address starts after @ and ends with .com.

Email Address

Email address example; or When your email sender server communicates with the recipient email service provider servers, the email sender’s name (your e-mail address) gets provided.

All the above subjects get valued by the email service providers differently. For example, your Ip address can have a very high reputation for email deliverability. In contrast, your email address can have a lower standing for email deliverability. 

Your IP address is critical to keep clean for a better sender reputation.

Remember, all your emails are delivered through this IP address. Internet service providers always keep how many emails are received from a specific IP address, domain name, and email address.

Remember, we have the IP addresses at the top of the food chain.

You always need to monitor all aspects of your business email deliverability. We will mention step by step why the above values can get affected, how you can avoid making any mistakes while choosing an email sender service, how many emails you can send per IP address or email address, and domain to many other subjects.

Let’s move to the next topic.

No more spam folder.
No more spam folder. Do not trigger spam filters. Pass through spam filter checks.

The difference between email delivery and email deliverability

Email delivery is delivering the email to your recipient’s email server. So your email is delivered. The percentage of the emails delivered is called as email delivery rate.

IE, you send 10.000 emails, and 100 of your recipients either the server did not respond, or those customers’ email addresses don’t get used anymore and are invalid. So 1% of your email soft bounce or hard bounce. Your email delivery rate is 99%.

What is Soft Bounce and Hard Bounce? What are the differences?

SOFT BOUNCE: The recipient’s server was unavailable when you sent emails. Your email server will re-try sending it later on.

Usually, when there is a soft bounce, email service providers re-try sending in 5 minutes, then in 15 minutes, 30 minutes, 60 minutes, 4 hours, and one day. If still not received, it gets a hard bounce.

HARD BOUNCE: The recipient’s server receives your email. However, the recipient’s email address is incorrect, and the service provider sends a message back to your email server. This is called a hard bounce.

What is a good email deliverability rate?

About email deliverability, let’s assume you have 10.000 customer email addresses in your email list. You spend hours or even, in some cases, days on an excellent email marketing program.

After you send emails to your customers, you expect many of them to open them. But due to soft and hard bounces, spam traps, IP reputation, domain reputation, email reputation, and disposable or temporary email addresses, you might get between 10 to 30% open rates.

Your open rate shows your email deliverability. In the current email marketing industry, over 30% open rate is very good number.

Email Validation Process
Email campaign success with bypassing spam filters and sending emails to subscribers inboxes.

Validate email addresses in your Email List. Be nice to internet service providers.

Internet service providers want to receive verified and cleaned emails before sending them. Verifying your customer emails if they are real and active significantly affects your sender reputation and email campaigns open rate.

What is email verification?

Email address verification involves various techniques to check if the email address is valid, invalid, spam trap, disposable/temporary email, or accept-all.

Valid Emails are active and working email addresses.

Invalid emails are emails that are not actively used by the owner anymore.

Spam Traps are the unique email addresses that email service providers use to monitor which companies are sending emails. Those emails never get opened, or sometimes they become overloaded, making inbox placement impossible.

Service providers know this, and they check if you are still sending emails to the full inboxes.

Spam trap emails are the scariest type of emails for email marketing. You should never email these email addresses for your marketing success. Otherwise will have a poor sender reputation.

Consider that most of your emails will land in the spam folder on such email types. And, if you continue sending emails to these email addresses from various email addresses of your business, your domain reputation also gets affected.

Disposable/Temporary emails are the email addresses generated randomly by your customers just to signup for your service. These emails are only used once, and they never get monitored anymore. Sending emails to these email addresses lowers your email deliverability.

Accept-All emails are a type of configuration made by email service providers. Whether an active and real email address is valid or not, these email providers accept your email and never return any information. So your sender email server can’t know whether your email bounced.

You may read more about the email validation process here:

Email Sender Reputation
Email Sender Reputation

How often should we validate email addresses to have a higher sender reputation?

Validating email addresses in your email campaign lists significantly improves your email deliverability. For the email deliverability best practices, we suggest verifying your customer email in the following schedule:

  1. Twice a year for all your customers’ email addresses
  2. Every quarter for the customers signed up to date in the last year.
  3. Every month for the customers signed up to date in the last three months.

Validating your new customers’ email addresses more often than older ones may sound different. You would expect older customer emails should drop into an invalid state. However, eliminating problematic emails when they sign up lowers the chance of invalid emails.

Validate all your customer email addresses in a shorter schedule, which will help your email deliverability and sender reputation. You get better inbox placement which will generate a better sender score.

How can we validate our customers’ email addresses?

Email verification process proper email infrastructure with unique capabilities set up only for this type of business. There are various verification service providers. You can find a short list of the best email verification services that can increase your email deliverability:

  1. Emails Checker Pro
  2. Bouncer
  3. Zero Bounce
  4. Never Bounce
Emails Checker Pro
Better domain reputation & no more emails dropping to spam folders. Free signup.

As Emails Checker Pro, we are providing the cheapest solution in the industry that works with the most accurate results. Try any of the services with your list and compare yourself to find the best one for increasing your sender score.

Remember, Email verification is an essential tool to lower your spam complaints.

Monitor your customers’ email open rate. Only send emails to the customers who are opening your emails. Always focus on better sender reputation and email deliverability!

Avoid spam traps and blacklists.

We want to take your attention to spam traps once more. Spam traps and blacklists are critical subjects regarding IP and domain reputation.

Your mailing lists can have thousands or millions of email addresses. Some of these emails opt into your list through email provider bots to analyze your business reputation.

After these bots opt into your email list, they monitor how many email messages you send to your customers and analyze each email with their algorithms.

From time to time, these email service providers send back a message to your email sender server that your client’s email address is full. Sometimes they can say that it’s not valid anymore.

They continue to monitor these email addresses and wait if you would send emails to these email addresses again even though they told your server that these are full inboxes or invalid email addresses.

If your email server continues to send emails to these specific addresses, email providers continuously lower your sender score and move your emails into the spam folder.

Email validation services like Emails Checker can quickly identify these spam-trap email addresses and remove them from your mailing lists.

Single opt-in vs double opt-in
Single opt-in vs double opt-in

Use Double (Rather Than Single) Opt-In for Your Lists

Opt-in refers to allowing customers or recipients of an email to give their company emails that feature promotions. The standard form is one or two opt-out forms / two opt-out forms / two opt-out forms.

It’s the best practice to double opt in before you add an email address to your marketing email list. Usually, websites do email verification when a customer signup to the service. The customer needs to open their email and click the verification link. Email verification is a type of opt-in process.

However, when you need to move these customers into a different email list for your marketing campaigns, asking these customers to double opt in to these new campaigns is a good practice.

Email service providers functions
Email service providers functions; bulk segmentation, email polls, reply tracking.

Email Service Providers and Email Marketing Success

Managing your own SMTP email-sending server is time-consuming and requires experienced engineers to monitor your sender’s reputation through various tools continuously.

Companies usually use 3rd party email deliverability services to overcome such issues for email marketing program.

Here are some of the companies that are best known for email deliverability:

  1. Mailchimp
  2. Drip
  3. Mailerlite
  4. Constant Contact
  5. Send Email Marketing

Email service providers are focused on getting your customer emails into your mailing list immediately and getting explicit permission for delivery. They have a huge infrastructure and can deliver emails in a brief time period to your customer inboxes.

All the companies mentioned above are the best in this niche market. When you read the below content, you will understand your exact needs and the packages you need from these services.

These companies do all the best setup for email deliverability, like domain keys identified mail and domain based message authentication. So, you or your network engineers never have to work in detail to setup the best config for your company email message reputations.

How can email services help for IP Reputation?

All email messages are sent from computers with an identifiable address (the IP address). The IP address can be connected to specific senders; therefore, the ISP can track the sender quickly and effectively.

IP Reputation is measured only by the IP address from which a message arrives. i.E. IP address. Those companies have no connection to this website or the emailed content. Identities and reputations can get you into the recipient server. In most cases, the sender has either a specialized IP address or is sent via shared IP pools.

Mainly email services are used with shared IP pools monitored and managed by these providers. Using such a marketing service, ensure you are sending your emails through a clean IP address.

Companies separate their sending email IP addresses into two categories; transactional emails and marketing/campaign emails. Let’s look at what these are.

Transactional Emails
Transactional Emails

1) Transactional emails

Transactional emails are emails businesses send to their customers only for important and system-specific cases. These emails must land in subscribers’ inboxes and should look clear on every email client.

For example, the initial email a company sends to their customer when the customer signup for their service is a good example of a transactional email.

Emails like “payment received “, and “sending invoice” are also considered transactional emails.

These emails has to reach to the customers email address and these emails do not have an unsubscribe link below the email. A customer can not unsubscribe from these emails.

Bulk & Marketing Campaign Emails
Bulk & Marketing Campaign Emails

2) Marketing email delivered

Email marketing is very critical for every business for its success. Managing spam emails, working with email providers, and choosing the right email program are essential.

Even though you only send legitimate emails to your customers who approved to receive emails from your business, an email message can get identified in spam reports by spam filters and land in your customers spam folder.

Also, your customer can mark your email as spam even though it wouldn’t be. These spam complaints reach your customers’ email server and lower your business email reputation.

Email marketers trust email services in this case. So they can monitor the rate of spam complaints from which users, which email campaign receives more spam complaints, and they can avoid spam complaints easily.

Also, email services are using a different set of IP addresses when sending your business marketing emails. So even if your reputation in the marketing emails gets lower, your transactional email deliverability stays perfect.

Email service providers continuously monitor their own IP reputations and if any Ip starts getting a lower reputation they remove this IP from the pool and assign a new IP address.

Let’s continue to review whether it’s better to use a pool of IP addresses or dedicated IPs when reaching your customers email servers.

Dedicated or Shared IP
Should we use dedicated or shared IP for mailing lists and better inbox placement?

Decide between Shared and Dedicated IP addresses for sending.

Remember that your IP identifier can also affect your email reputation. Platforms that can send a series of messages simultaneously offer standard shared IPs whose usage can be seen across hundreds or millions of users. This will help reduce costs for your service but is not guaranteed to control your IP reputation.

Operators are careful in ensuring good quality and rotate a hundred IP addresses to guarantee reliable service delivery to customers if needed. Most of the time, sharing IP is sufficient.

Shared IP Address

Shared IP Address is a pool of IP addresses provided by email sender services. It’s a good choice for businesses if they don’t sender more than hundred thousands of emails every month.

Your email service providers manage IPs, and they continue to monitor the reputation status of these IP addresses. However, other businesses also share the same IP address when sending email campaigns, which can cause a poor sender reputation.

Benefits of using shared IP addresses

  1. No need to manage and monitor your IP reputation
  2. Already accepted IP addresses by internet service providers. No need for warming IPs.
  3. Easier to set up DNS records of your company domain.
  4. Easier to manage domain reputation.
  5. Easier to set up DomainKeys identified mail.
  6. Theoretically, you can send an unlimited number of emails.

Dedicated IP Address

A dedicated IP Address is a single IP address. This is an IP just assigned for your business domain name. Your email server uses this specific IP when sending an email marketing.

Your business is responsible for managing and monitoring your IP address’s reputation status. However, no other business can use your IP address and you are safe from other companies affecting poor sender reputation.

Benefits of using a dedicated IP address

  1. Single IP Address reserved for your business domain.
  2. Your IP reputation does not get affected by other businesses email deliverability and email activities.
  3. Send all your emails from the same ip address. This makes it easier to monitor the sender reputation and sender score.
  4. No one can send malicious email campaigns using your IP address as it’s locked for your business. Have a better sender score, and malicious senders can not use your IP address.
High volume email sender chart example
High volume email sender chart example

High Volume Sender? – Opt for a Dedicated IP Address

Suppose you are sending emails more than a hundred thousands of emails every month. It’s suggested to have your own dedicated IP address and monitor your own reputation.

Email deliverability is one of the most serious parts of a business marketing. Email addresses are key for companies to identify their customers.

So managing your Ip reputation is critical. Do not leave this task to 3rd party businesses. However, there are online tools you can easily monitor your IP reputation. In the next header, we will provide details of Ip reputation tools.

If you need any help with your Ip reputation monitoring and management, you may reach our 24/7 live support here:

We are not in the IP reputation management business. However, our expertise is very broad, and we can help our customers.

Email Sender IP Blacklist Check Tools
Email Sender IP Blacklist Check Tools

Email Blacklist Check – IP Blacklist Check – See if your SMTP server IP is not blocked.

There are hundreds of different Ip reputation and IP blacklist-checking services. Email services and internet service providers are working with these 3rd party blacklist services to validate your sender score and sender reputation.

Having your domain or IP address listed in these blacklists usually lead to your email landing in your customer email client spam folder.

For example, a major mailbox provider iCloud does not allow any communication coming from an Ip address listed under Spamhaus IP Block List. As we know also Hotmail and Proton Mail are validating sender IP addresses through Spamhaus.

It’s best to monitor your Ip reputation continuously. However, this is a very complex task for someone to monitor your Ip reputation every day from 100s of blacklists.

Here are some of the well-known services you can use to run these checks every day for you and keep you updated as soon as your IP or domain gets listed in one of these blacklists.

Here are some of the major tools you can use for your business email sender dedicated IP addresses reputation checks:

We are using hetrix for our business dedicated IP addresses monitoring every 24 hours.

Email Spoofing
Email Spoofing

How Spammers Use Email Sender Spoofing

Somebody can send email messages from a website such as They change some header values, so ISPs will think Mark is trying to make a call.

The spoof of e-mail is incredibly useful in allowing spammers to impersonate a website and send you an email campaign to trick you into the customer account. Okay. Fortunately, this won’t have any difficulty. Mail service providers are improving detection. Almost all of them perform identification checks on new email accounts.

However, there are ways to block sender spoofing with proper SPF and DKIM setup for your domainkeys identified mail verification. We don’t want to get into details of this setup, but you may read details here:

How to improve email deliverability: Best practices for your email campaigns

What is the best way to improve email delivery? What measures we can take with our email campaigns for better deliverability?

There are a few main rules to obey, and let’s discuss each of them in more detail:

Send emails only to users who want to receive them.

Sending emails only to your customers is critical. Your customers are the people who are interested in your business subjects. When they receive your email, these people tend to open your email campaign.

Email service providers monitor the number of people you are sending emails from those services. They also monitor the rate of open rates. The more open rate you have, the better email delivered in the long run.

You don’t want anyone else to receive your emails.

Unsubscribe link example in an email.
Unsubscribe link example in an email.

Have an Unsubscribe link below your marketing emails.

The whole thing may need to be more intuitive. Why do people let their mailing lists fall away? Usually, you are subscribed to mailing lists but have yet to open the email.

Your friend signed up for ebook download years before and didn’t care.

You might have been interested in some blogs but have yet to have time. It is possible that hundreds more people will not contact you right now.

Having unsubscribe links in your emails is very important. This secures removing the emails from your email lists that don’t want to receive your emails anymore.

If your customer doesn’t click an unsubscribe link, they can mark your email as spam. So future emails will drop into the spam folder. But you continue to send emails to the same customer. This means your open rate will drop.

It’s a better practice to remove these customers from your email list rather than sending them to their spam folders.

Attractive Subject Lines
Use attractive subject lines for better email open rate

Attractive Subject Lines

When your customer receive your email, the first thing they see is your email subject lines. So having an attractive subject line will higher your email to get opened.

Many email marketing sending services like Send Email Marketing provides A/B testing for both email subject lines and email content.

Subject line A/B testing allows you to test multiple subject lines with a limited percentage of your customers. Whichever subject line gets more open rate or click rate, email marketing sending services send the remaining emails with the highest open rate subject line.

Send Emails To Only Valid Email Addresses

Let’s assume you are sending 1000 emails in total. In scenario A, 99% of your emails reach to your customers email clients as you have 1% invalid emails in your list. In scenario B, 90% of your emails reach to your customers email clients with 10% invalid emails.

For internet service providers, the company with scenario A have much higher email reputation because of higher email deliverability from the business domain and IP addresses.

Validating your email list to check email if they are valid or invalid is important before sending your campaign. You may refer to the subject above we’ve mentioned about email validation.

Create a clean list.

Customer email feedback loop chart
Customer email feedback loop chart

Feedback loops

Simple tricks to increase your email reputation can get used with the feedback loops.

Feedback loops are emails you put in between your marketing campaigns with your drip emails. They are used to trick your customers into replying to your emails.

When internet service providers see more activity with your emails, they also increase your email reputation and deliverability—especially free email services like feedback.

Hotmail or Yahoo feedback has more priority than many other services.

Send from Authenticated Domains

Authenticated e-mails mean your receiver email service authenticates the email sent from the correct IP and domain address.

Professional email marketing services direct you on how to authenticate your domains.

Make sure that your IPs are properly allocated.

Follow a consistent schedule.

ISPs are also grateful for implementing regular emails. Users are more likely to receive and view emails when they regularly come, such as Tuesday afternoons.

It could be deemed suspicious by the e-mail provider to receive an extra email every time.

Avoid temptation and give everyone an update immediately. Instead, include it in the campaign. Emails are a good way of boosting conversions and improving your reputation. The time between 9:30 and 10:30 is a good start.

Test and monitor your email open and click rates to find the best day to send email newsletters and the best time to send these campaigns.

Segment: Inactive (More than 90 days old, never opened or clicked an email)

Every month moving the customer emails who have not interacted with your emails in the last 90 days to a different segment is an excellent practice.

You must remove these emails from your main marketing list. Do not send the same frequency of emails to these customers.

Segment: Lapsing (More than 1-month-old, last activity 91-180 days ago)

Segmenting your customers! Segmenting your customers who are getting a little older than your new customers added to your email list is essential.

Identify who is more interested in your business and who is not, and focus on the more active customers.

Always Include a Plain-Text Version Along with Your HTML Campaign Version

Some email clients don’t load the HTML version of the email for security reasons unless the user clicks view in the HTML link.

To ensure your customers can see your email, email sender providers can generate a plain text version of your HTML email and send both to your customers’ mail clients.

No-Reply Emails
No-Reply Emails

Don’t Use a “No-Reply” Sender Address

It sounds like sending emails from a no-reply email is a good idea. However, it’s the opposite. Usually, no-reply emails are not real active emails. Even though you activate such emails in your email server, your business never monitors these emails.

Using a no-reply email means you will never interact with these emails. Also, your customers will not reply to these emails. Remember, we have mentioned that interaction is vital for your email deliverability and your sender’s reputation.

Make sure to send your email campaigns from your business support email address. Your customers can reply to these emails instantly.

There is another benefit of using support emails as sending emails. When your customer opens a ticket and your support team replies, if your email drops to your customer’s spam folder, your customer will mark it as not spam. Your email sender’s reputation will continuously increase. You will automatically improve your email deliverability with no additional effort.

Also, using your support email will help you get feedback loops.

Send Relevant Content That Your Subscribers Want to Read

Your customers signed up to your business and email list to receive content relevant to your service. These people will only like to receive email content related to your business.

You may send any content relevant to your business. This can be your business news, new function updates, or discount offers. But everything should be around your business.

History shows any email you send to your customer that’s not related to your business will get your email marked as spam and lower your sender’s reputation.

Email Deliverability Frequently Asked Questions
Email Deliverability Frequently Asked Questions


How do you deal with an ISP blocking your emails?

Contacting blacklisters is easy. Check your IP address if it’s listed in any blacklist. Most domain blacklisters provide a form for removing IP addresses or domain names from their blacklisted list.

You must provide domain names, contact details, and valid reasons to delist.

How to test email deliverability?

There are 3rd party tools that can do this for you. However, we suggest you do your tests manually. You can send emails to your own Gmail, Hotmail, Yahoo, or iCloud email addresses and check if they land in inboxes properly.

When you do this monitoring, if any of your emails drop into your spam folders, move them into your inbox or mark those emails as not spam.

Can we automatically validate and clean our email list?

Some of the email validation services can provide email validation API for their customers. These API services are beneficial for companies to automatically clean their email list to get rid of invalid email addresses.

Businesses can connect their backend to these email validation systems through API and check for every email address they are communicating with before they send an email.

This process can take between 3-10 seconds. However, it takes a lot of work to have a clean list of customer emails and send emails to only valid email addresses.

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