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Transitioning to Customer.io as a sender

There will always be some measure of deliverability performance variability when you start sending from a new email provider. This article should help you navigate this critical transition and avoid problems.

What is a sender identity?

Your sending identity, sometimes called a sender “fingerprint,” is comprised of:

• Sending domain
• Sending IP
• Other non-public fingerprints

Every inbox provider tracks your sender identity differently. The goal of establishing sender fingerprints is to properly identify senders and calibrate their reputation and anti-spam systems based on historical behavior and performance.

When you move to a new sending platform, some aspects of your sender identity will change. While some changes are more impactful than others, there is always going to be a measure of performance variability with your deliverability when any part of your sender identity changes.

What changes when you send from Customer.io?

When you start sending emails from Customer.io, two things happen:

1. You’ll send from new IP addresses
2. The actual domain of your From addresses changes. There are two types From addresses at play:

Display-From: This is the domain that your audience sees in the From address field in their inbox clients—for example, hello@customer.io. In this case, customer.io is the visible domain.

Envelope-From: This is the domain that is actually signed with SPF / DKIM and communicates with your recipient’s server. When sending from Customer.io or other similar platforms that send email on behalf of your domain, this domain can sometimes utilize a unique subdomain that differs from the root domain. While many email-sending platforms utilize an entirely different subdomain, we simply add a unique subdomain to your existing root domain for better deliverability and Return-Path parity. When you send from Customer.io, your envelope’s from domain will always be in the format: cio#####.mydomain.com where ##### is your account number.

While your recipients will always see your domain or subdomain in the From address, a unique subdomain is created for use as your Envelope-From address.

Easing the transition to Customer.io

In your first weeks of sending email from Customer.io, the following critical steps will minimize the impacts of sending from a new provider.

Start slowly

Above all else, you should start slowly when you send messages from a new provider. While there aren’t any hard-and-fast rules, your best bet is to start with a small list—no greater than 1000 recipients—and slowly increase your sending volume over a couple of weeks. This allows inbox providers to recognize your new sending source and properly calibrate their inbound systems accordingly. If possible, you should only send to recipients who have recently engaged with your emails during this critical time, which leads to our next piece of advice….

Import engagement data

Keeping track of your most engaged recipients is critical to deliverability success. The best way to do this is to identify recipients who have engaged with your messages in the previous 120 days in your old platform, and keeping track of these recipients in Customer.io by adding an attributeA key-value pair that you associate with a person or an object—like a person’s name, the date they were created in your workspace, or a company’s billing date etc. Use attributes to target people and personalize messages. Attributes are analogous to traits in Data Pipelines. to engaged people. For example, you could identify your most recently-engaged recipients and then import these recipients to your Customer.io workspace with an attribute of recently_engaged: true.

You can then create a segmentA group of people who match a series of conditions. People enter and exit the segment automatically when they match or stop matching conditions. for people with this attribute and use it to ensure that only engaged people receive your messages.

Import suppression lists from your previous provider

To ensure that you don’t inadvertently send email to recipients that experienced hard bounces or were suppressed for other suppression reasons, we recommend either importing your suppression lists (by reaching out to our support team), or, simply not importing any recipients on these lists to Customer.io.