Maximizing Deliverability

This document discusses various topics related to email deliverability and how to manage it.

# Email collection best practices

CAN SPAM mandates that subscribers must opt in to promotional email. In other words, you must have their explicit permission before emailing them.

Do not use Iterable to send messages to purchased subscribe lists. If do this, you risk having your Iterable account suspended and are subject to a penalty fee.

If you'd like to send messages to a list of addresses acquired from a third party, you must be able to prove that all subscribers on the list have given you permission to message them.

# Single vs. double opt-in

Single opt-in subscription allows users to sign up for mailing lists or services without needing to confirm their email addresses. Double opt-in subscription requires users to click a link in a verification email before adding them to the list.

Since they require an extra step for users, double opt-in subscription practices result in fewer sign-ups. However, they also result lists of verified, valid email address, which reduce bounce rates and improve deliverability.

When using single opt-in subscription, it is a good idea to run your lists through an email verification service (such as Kickbox) before sending.

For more information about setting up single and double opt-in subscription processes with Iterable, read Build a Welcome Sequence for New Subscribers.

# Email authentication (SPF, DKIM, DMARC)

When updating your DNS records, you'll enable SPF, DKIM and DMARC. These email authentication techniques help improve deliverability.

SPF (Sender Policy Framework) checks to make sure that incoming mail from a domain comes from a host authorized by that domain's administrators.

DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting and Conformance) are both designed to detect email spoofing. They allow ISPs to check that email was sent from an authorized domain and that it has not been altered.

# Bounce management

There are two types of bounces: hard and soft.

Hard bounces happen when sending an email to a misspelled or outdated email that's no longer in use. Iterable automatically unsubscribes hard-bounced users from the sending message channel.

Soft bounces happen for a variety of reason: a full mailbox, rejected content, out-of-office messages, messages that are too big, no detectable reason, etc. Iterable does not automatically unsubscribe soft-bounced users. To manage soft bounces, periodically check for email addresses that have bounced five or more times during the past three months—a sign that an email address is no longer valid or that the user no longer checks the mailbox.

# Channels and message type subscription management

Iterable can send of emails from multiple channels.

Using separate channels (or IPs) for marketing and transactional email isolates deliverability problems. This isolation prevents an impact to the deliverability of your business-critical transactional in cases where many users mark a marketing message as spam.

To learn more, read Message Channels and Message Types Overview.

# Frequency limits

Iterable has a built-in rate-limiting feature for marketing channel emails: a single email template ID cannot be sent to the same user more than once every 18 hours.

Additionally, for a journey you can enable Limit Simultaneous Journey Entrances Per User to prevent users from entering more than once at a time. This feature is useful for a welcome series or cart abandonment campaign.

# To field customization

Customizing an email's To field improves deliverability by confirming to ISPs that you know the first and last name of the people to whom you're sending.

To enable this feature, navigate to Settings > Project Settings. Then, in First Name Field and Last Name Field, specify the Iterable user profile fields in which your project stores the first and last names of your users.

# Sending best practices

• Use an easy-to-recognize sender name and email address.

  Make sure the sender name and email you use is easily recognizable as being associated with your company.

• In your subject line, avoid spammy words such as "FREE" and "ACT NOW!" Your preheader text should also be in line with your subject line and provide relevant and inviting information.

  To learn more about words to avoid, read Mequoda's Subject Line Spam Trigger Words article.

• Keep messages below 103KB. Otherwise, they will be clipped.

  Gmail clips messages above 103KB. If your email is too big, you will see the following message from Iterable:

  

  To prevent this from happening, keep emails short and direct.

• Remind users why they receive your messages.

  It can help users to see an explicit reminder as to why they have received a message. For example, you might include text similar to the following: "You are receiving this email at {{email}} because you signed up for a mailing list on our website."

• Ensure that your send lists contain valid email addresses.

  Hard and soft bounces can negatively impact your sending reputation. To minimize them, use a tool such as Kickbox to verify your lists before sending.

• Suppress users that have bounced or marked a campaign as spam

  Use Iterable's segmentation tool to create suppression lists that segment users by bounce or spam complaints.

# Maximizing opens and clicks

To maximize email open and clicks, consider these ideas:

• To increase the likelihood that users receive your emails at times when they're likely to read them, consider their time zones when sending. For more information, read Creating Blast Campaigns.

• Use buttons to highlight the primary calls to action in your messages.

• Fill your emails with engaging, useful, appealing content. For example, promotions for products and services can encourage people to interact with your messages.

• Less is more. Users are most likely to engage with content that is direct and to-the-point.

• Use responsive email templates to ensure correct display on all devices (subject to how well the email client respects/supports the provided HTML).

# Subdomains

Using a subdomain-based sending address can help clearly associate marketing emails with your company's brand, while at the same time isolating them from the sending reputation of your corporate root domain.

For example, you might use a subdomain such as: email.yourcompany.com or sellers.yourcompany.com.

# Seed testing

To seed test an email, send it to a list that includes many different email services (Gmail, Outlook, Yahoo, etc.). Then, verify that these services accept the message and inspect where they place it in user inboxes.

Iterable does not provide seed testing services. Consider using 250ok.

# IP reputation monitoring

IP reputation monitoring notifies you if your IP address is included on an email blocklist. Iterable does not provide IP reputation monitoring, but there are various services (such as Return Path) that do.

Since Iterable does not have a freemium plan and carefully vets new clients, its shared IP address range typically have very good sender reputations. As you initially configure your DNS, when using shared IP address ranges it's best to "warm up" your domain by sending first to your most engaged recipients.

When using a dedicated IP address, you are solely responsible for your IP address reputation. As a result, it may be a good idea to use an IP reputation monitoring service.