8 Expert Tips for Successful Email Deliverability

Maintaining good sender scores and email deliverability rates is an ongoing battle. Here's 8 important tips for successful email deliverability rates and healthy sender scores.

Email Deliverability is crucial to any business or online marketer. If your emails only reach 20% of your clients or leads, then you are significantly limiting your success. It's quite common to think that sending email is a very straightforward process, but landing your messages into a recipient's inbox folder is quite a challenging task.

According to a study by ReturnPath, only about 81% of sent emails are delivered to the subscriber's mailboxes. The number is often quite lower for businesses that currently struggle with getting their messages into a client's inbox. Many factors can affect deliverability rates, and it's often referred to as not an exact science. However, it is easy to understand that it can have huge consequences for a company's ROI and growth.

Email Deliverability

What is Email Deliverability?

Email deliverability is best explained as the level at which messages sent by email reach the recipient's inbox, rather than their spam folder or being completely rejected by the mail service provider. Often times, mail service providers are overly aggressive in their spam filtering and block legitimate email. Email delivery is crucial to the success of any marketing campaign or even for transaction email messages that alert your users or clients.

How Do You Improve Email Deliverability?

Human-Friendly Content and Subject Lines

Clean, direct content and subject lines that are human-friendly will greatly improve click through rates of your email marketing, as well as the retention rate. SPAM filters scan attachments, text content, and embedded scripts for any suspicious behavior. Attachments raise your chance of hitting the SPAM folder, as well as spammy text, and even embedded tracking code. Keep your messages as clean as possible to reach the inbox.

Quickly score your email addresses with mail tester to determine if the content or subject will trip any SPAM filters.

Authenticate Your Email With DNS Records

Today's best practices for successful email deliverability rates requires healthy DNS records that authenticate email address sent from the domain. SPF, DKIM, and reverse DNS (rDNS) records are a necessary foundation that must be met if you don't want to end up in the SPAM folder. Once an ISP or mail service provider receives a new email, they will check these records before processing the content and other factors that contribute to the sender score.


DomainKeys Identified Mail, also known as DKIM, is now commonly used by all mail service providers to validate the authenticity of email messages, as well as the sender. As an email is sent, a DKIM signature is applied to the message by a private key and validated on the receiving email server (or ISP) by a public key listed in the sending domain's DNS records. This process verifies that the message was not modified during transport.

Having emails signed by DKIM is more legitimate to its recipients and less likely to access folders or Spam folders. Like SPF, DKIM pass through is required for "Message Authentication, Reporting and Compliance" DMARC, a newer standard for reducing SPF and DKIM email spread. In addition to verifying the authenticity of an email, DKIM also provides a way for ISPs to track and build a reputation based on your domain's sending history.

DMARC is based on two other authentication protocols: Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM). You must have SPF and DKIM in the domains before you can proceed with DMARC.

Implementing Domain Based Message Authentication Reports and Compliances (DMARC) is the best way to protect your customers, your brand, and your employees from hacking and spoofing attacks.

Therefore, we strongly encourage you to subscribe to SPF, DKIM and DMARC with your domain, allowing you to build a reputation instead of using our upload domain. This reputation is portable and will help you monitor your reputation and publish practices across multiple sources.

Implement a Policy Framework for Senders

A sender or SPF policy framework increases its reliability in the eyes of the receiving mail server. The server can check the domain name with the associated IP address to make sure it is legitimate. If you do not have SPF, your emails may be rejected.

Send Emails From a Dedicated IP Address

The domain and IP address of the email's sender plays an important role in ensuring healthy email marketing deliverability. IP addresses are easily blocked once SPAM or unsolicited email is detected as originating from that IP. If you send mail from an IP address that is shared by other senders, you are putting your email deliverability rates at risk, as shared IPs are frequently blacklisted. Therefore, it is strongly recommended to purchase a dedicated IP address so you can fully control its reputation.

Whichever type of IP address you use, it's best to ensure that your IP addresses are not blacklisted by any major providers with a free blacklist check.

Improve your deliverability rates with expert advice and email list hygiene.

Monitor Feedback Loops

Most ISPs provide network loops through which the email sender can obtain information from the recipients who have complained about that sender's email. These are called FBL feedback or complaint loops.

AOL, Yahoo, AOL, and Microsoft make it easy to obtain this information. Gmail allows users to configure a backend loop that does not use the traditional ARF format of most FBLs.

Only email service providers (ESPs) can access the Gmail FBL program. This can also be setup with a DMARC record.

Clean Your Lists Regularly

Make it easy for users to unsubscribe from your list that are no longer interested in the content. It's also helpful to display why a user is being contacted by your company, for example "You are receiving this message because you recently signed up as google.com". Including an unsubscription header also seems to score favorable points with Gmail and larger mail services, which make it easier for users to automatically unsubscribe through their mailbox.

Verify Your Recipient Email Addresses

Healthy deliverability rates require active users and active inboxes. When you send an email message to an inbox that no longer exists or is inactive, a message will be sent back to you with an error. This process is referred to as a "bounce". High bounce rates hurt you domain and IP's sender score and can quickly get you blacklisted by the most popular mail service providers. If you are using a service to send your mail, such as MailChimp, SendGrid, aWeber, and similar services - you can expect your account to be banned if your bounce rate exceeds 10-15%. Mail service providers will begin penalizing your domain and IP address with as little as 2-3% bounce rates.

So how do I ensure my recipient emails are valid? IPQS Email Verification handles this process, taking an email marketing list and automatically removing invalid, inactive, or unhealthy email addresses. It's also possible to implement our Email Verification API directly into your platform to automate this process.

Removing invalid email addresses keeps your bounce rates at healthy levels so mail service providers do not blacklist your domain name or IP address. Good bounce rates can also improve your sender score, as they indicate to an ISP or MSP, that you are sending mail to quality email addresses, rather than blasting messages to random mailboxes.

Remove Spam Traps

Mail providers commonly use Spam Traps and honeypots to identify unsolicited email that is then used to determine which domains and IP addresses should be blacklisted. Hitting one spam trap will not instantly cause damage to your reputation, but multiple spam trap hits within a short time period will significantly impact email deliverability. Removing spamtraps is a top priority and equally as important as validating email addresses for avoiding SPAM folders and blacklisting.

Email Deliverability Recap

Hopefully this article highlights the key ways you can improve email deliverability to run successful email marketing campaigns and even transaction email for your users. If you currently have issues, the good news is that you can do a lot to improve email deliverability and resolve any issues. Your main goal for high quality email deliverability is to improve the sender's reputation and ensure that ISPs trust your IP address and domain.

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