Deliverability
Did you know?
21% of opt-in emails never make it to the destination's inbox.
Your newsletter has to go through a series of checks and various tests before reaching your recipient's inbox. If your message fails to meet the standards of proper emailing, it will most likely end up in your subscriber's junk folder and they probably won't even know it.
Regardless of the size or industry of the sender, every mailing address gains a reputation that impacts your deliverability. Here are key factors that can affect your sender reputation.
Factor |
Description |
Bounces |
There are two types of bounces: hard bounces and soft bounces. Hard bounces may indicate that the list is not clean and can be targeted by spam traps. Too many hard bounces can result in bulking/blocking issues. The recommended threshold for hard bounce rate is 2%. |
Complaints |
A spam complaint occurs when a subscriber flags your email as junk. This can happen if the email is unsolicited, sent too frequently, contains irrelevant content, or the recipient cannot determine who sent the email. Complaint rate is important because it is based on the recipient's perception of the sender. |
Engagement |
Engagement can be either positive or negative. Positive engagement from a subscriber would be opening, clicking, adding sender to their address book, enabling images, and scrolling through the email. |
Spam Traps |
Spam traps are email addresses controlled by ISPs and anti-spam organizations for the purpose of catching and identifying illegitimate senders. |
Volume |
ISPs have automated filters that monitor for any unusual activity, so that their users are protected from spam. Sending inconsistent volumes and/or at irregular frequencies may trigger spam filters and damage the overall deliverability. |
To ensure a high deliverability rate, here are some tips that can help boost your chances of delivery and lessen the risks of being flagged as spam.
Consistency
Sending emails regularly will increase your sender reputation with ISPs as they are looking for consistency. They are also looking at your analytics (deliveries, hard bounces, complaint or unsubscribe rates, etc..) to see if there aren't any irregularities that could trigger their spam filters.
Quality over Quantity
A quality list where your recipients are actively engaging with your newsletter positively (opens or replies) shows sign that you a legitimate sender, thus increasing your sender reputation with ISPs. Sending emails to a large list consisting of bounces or people unsubscribing from your newsletter will decrease your sender reputation and can trigger ISPs spam filters. It is important to clean your list on a regular basis in order to avoid being flagged.
To ensure a maximum compliance, acquiring subscribers by the double opt-in method, properly processing bounces, and managing complaints will establish an genuine subscriber to sender engagement. Your sender reputation reflects on the quality of your list. Tactics such as list purchasing can erode your brand because it is a high risk, low reward strategy that will generate deliverability issues in the long run.
To learn more on how to manage a quality list, click here.
Content
Sending emails that are too small can trigger ISPs spam filters. Your newsletter should have at least 500 characters to avoid being flagged as spam according to Email on Acid.
On the other hand, if your emails are too large because your newsletter contains images, make sure to compress their size to reduce loading time. Certain email providers will only show a portion of your email and it is up to the recipient to expand the rest of the content or not. For example, Gmail displays the first 102KB of the email and does not show the rest, potentially hiding your CTAs or your unsubscribe link.
If your newsletter is an image only email, this could also trigger ISPs spam filters since they can't detect any texts such as your address, your unsubscribe link, etc.. Certain ISPs block images by default, resulting in a blank email when your recipient opens it. Adding ALT tags (or image descriptions) to your images can explain to your subscribers what is meant to be shown.
For a more in-depth explanation about spam, click here.
Spam Trigger Words
ISPs also look for spam trigger words in your email and attribute a spam score to it. If your newsletter's total score exceeds a certain limit, then the email will go to the junk folder without your subscriber's knowledge. The score threshold varies between ISPs. One ISP can let your email pass, placing it in your recipient's inbox folder while another can block your email and put it in the spam folder. Your subject line is also analyzed by ISPs to make sure your email doesn't contain any misleading information.
Sending Domain Authentication
Authenticating your sending domain confirms email providers that your sender's identity is legitimate.
There are several common ways to authenticate your sending domain:
SPF (Sender Policy Framework)
This allows a specific IP address to send emails via your domain name by adding the IP address in your DNS record.
DKIM (DomainKeys Identified Mail)
This authentication method uses a public or private key system to sign emails in your DNS record.
DMARC (Domain-based Message Authentication, Reporting & Conformance)
This email-validation system allows the sender to verify whether emails have been properly authenticated by ISPs or webmail services.
To learn more about sending domain authentication, click here.
Ressources
Anti-Spam Recommendations for SMTP MTAs http://www.ietf.org/rfc/rfc2505.txt
Microsoft hotmail Policies https://mail.live.com/mail/policies.aspx
