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The Future of Email: A Technical Perspective

Florian Vierke, Senior Manager in Deliverability Services @ Mapp
The Future of Email: A Technical Perspective

One of the most important things for your brand is being individual and having a good reputation. Marketers have been aware of this for years and have been working diligently to contribute to this goal. Reputation is one of the most important key metrics in email. It’s why there’s currently a shift in the technical methods used to associate reputation with a brand.

It’s essential to be prepared for these changes. In this article, I’ll explore what alterations are on the horizon, why they are happening, and what actions are necessary in the future of email.

Email: A History

In the past, IP addresses have been the key reputation anchor. All the positive (opens, clicks, interaction, technical correctness) and negative signals (spam complaints, hard bounce, deleting emails without reading, missing TLS, etc.) contributing to a reputation have been collected based on IP. Unfortunately, relying solely on IP addresses doesn’t allow for the identification of a specific brand. This is because:

  1. Due to a lack of IPs, many senders use the concept of “shared IPs,” where several brands share the same IP address for sending.
  2. If brands use different technical senders, like different email service providers (ESPs), the IP will be different for each technical sender. This does not allow the merging of these separate reputations into a single one.
  3. Forwarded emails will only be identified by the forwarding IP.

And finally: IPv4 addresses are running out. While there’s a successor protocol (IPv6) that allows a much larger IP space, this IP space is so vast that the concept of reputation doesn’t make sense anymore for a single IP. The sheer size of the IP space would allow sending every single email in the future from a new dedicated IP for the foreseeable future.

Making sense of extremely large numbers is nearly impossible for human comprehension. However, I’ll attempt to draw a comparison: If you were to envision the entire address space of IPv4 as a square millimeter, the address space of IPv6 would cover planet Earth more than 150 million times over!

The Future of Email Reputation

The reputation anchor of the future will be the sending domain. Some of the large mailbox providers have already adopted the domain as the primary reputation anchor, with others following suit. Two main technical requirements for using the domain as a reputation anchor are crucial, and marketers must now pay attention to the following:

Technical requirement #1: Authentication via DKIM

Domain Keys Identified Mail (DKIM) involves creating a signature for your email and attaching it in the header. Recipients can validate this signature to ensure the email has not been modified or sent from a third party. A valid DKIM signature is the basis for a domain reputation.

Technical requirement #2: Domain alignment

Unfortunately, senders can choose a different domain in the envelope from-address than in the mail itself. On top of this, the email can be signed from a different domain. While being technically correct, this doesn’t offer the level of trust that we need for a domain reputation. Hence, the second requirement is to use the same domain in both the “From” (5322.FROM) and “DKIM-From fields.” If possible, the envelope from-address (5321.FROM) should also contain the same domain as well:

Example letters of choosing a different domain in the envelope from-address.

There’s A Link to Your Sender Logo (BIMI)– And iOS (v.16) Is displaying It

As highlighted in our previous post, these technical requirements form the basis for your BIMI logo to be displayed as a sender logo.

Example of BIMI.

When Apple’s iOS16 was released, they made it a point to support BIMI in their native mail app. This will mean a huge increase in displayed logos and make BIMI even more attractive than before:

List of ESPs that do, don't, or consider supporting BIMI.

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