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Promotional email vs. transactional email: Why it’s important to separate the two

Illustration of two mailboxes with "promo mail" written on one and "welcome mail" written on the other.

Chances are, you’ve heard the advice that you need to “separate your transactional and promotional email.” But what does it mean to separate your emails? Which emails qualify for separation? And is this truly a necessary step?

Today, we’ll answer those questions once and for all. That way, you can check this best practice off your list and focus on your next great idea.

Defining promotional & transactional emails

Before we go too far, let's define the specifics. You can lump most email messages into two camps—promotional and transactional. Here’s what we mean when we use these terms.

Promotional emails #

A promotional email (also called abroadcast or bulk email) is an email that is sent to more than one person that contains the exact same content and is not triggered by an event. A promotional email would be anything a customer did not specifically trigger, for example, a weekly newsletter, a marketing email, or an announcement about your site's recent updates.

We’ll review a few promotional email examples below.

Transactional emails #

Transactional emails are emails that your customer triggers. A welcome email after a customer signs up, an alert email a customer has set up in your app, an invoice email, and a comment notification all qualify as transactional emails. There are others as well, the exact nature of transactional email you send will vary according to the type of app you run.

Key differences #

There are some differences to note between these types of email:

  • Broadcast messages have lower engagement rates. Average open rates for promotional campaigns hover between 10-20%. That’s much lower than the 70% open rates that are typical for password reset emails. Engagement impacts sender reputation, and you wouldn’t want lower engagement on bulk emails to affect the delivery of critical transactional messages.
  • Transactional email delivery speed is measured in seconds. Time to Inbox matters more for transactional emails. When a customer needs to reset their password, a fast delivery is the number one priority. However, there's usually a little more leeway with promotional messages. In fact, sending too many broadcasts too quickly can raise a red flag with email providers. Separating transactional emails from broadcast emails creates a "high priority" lane for these time-sensitive messages.
  • Broadcast emails are more susceptible to human error. Different email types have unique vulnerabilities. Transactional emails could see bot attacks via spam using online forms. On the other hand, broadcast messages are more likely to involve human errors like sending to the wrong list or mismanaging data. Separating the emails allows you to troubleshoot and resolve issues more quickly.
  • Promotional emails require the recipient's permission. Customers have to opt-in to receive these emails, which also means they can choose to opt-out. But you need to be able to send critical transactional emails to all customers at any time. Separating these email streams makes managing subscriber's preferences a lot easier.

The reputation of the IP address, domain, and email address all play a role in getting your email into your customer's inbox rather than their spam folder. Or, in the case of Google, one of the inbox sub-categories like "Promotional". Email providers know that customers want and expect transactional emails, but it's not always easy for them to tell what's transactional and what's better classified as promotional.

Using separate domains or email addresses for each kind of mail makes it much more likely that your important transactional emails will get to your customers.

Shared IP addresses that only send one type of mail will always have a better reputation than shared IP addresses that send a mix of promotional and transactional messages.

Promotional email examples #

Let’s check out a few examples of good promotional emails.

The images used for the following examples are all courtesy of Really Good Emails, a great source of inspiration on how to do email messaging the right way!

Discounts #

When you think of a promotional email, it’s discount emails that likely come to mind. These are your Black Friday, back to school, and buy-more-save-more emails ubiquitous with eCommerce. As Avocode proves below, though, discount emails are for services and apps, too.

Image of Avocode's discount email.
Avocode’s discount email gets straight to the point. The discount value prop is in big, contrasting letters with social proof below to seal the deal.

Upsells and cross-sells

When you’re ready to take things to the next level with a customer, an upsell email comes in to save the day. A common place to find broadcast upsell emails is at the end of an onboarding series or when you introduce a new service level.

And sometimes sending an accompanying email makes more sense than an upsell. Shopify uses the cross-sell email below to offer a solution to a challenge a new user may be facing, and conveniently, it’s for a product they own.

Image of Shopify's cross-sell email encouraging customers to try another offering.
Shopify knows that sellers without a product won't stick around long, so they introduce dropshipping.
Image of Glitch's upsell email.
Glitch sent an upsell email when they launched a new paid plan.

Transactional email examples #

Transactional emails have been Postmark’s bread and butter since day one, and we love to share what we know about getting them right. Here are some of our recent favorites.

Registration and double opt-in #

Transactional emails are often critical, starting with account registration. When someone is creating an account, quickly getting a registration code to their inbox is essential to the user experience. The same is true for a double opt-in message.

Image of an Miro's authentication email.
Miro gives users the option to enter an authentication code or click a button to confirm their email address. Image via Really Good Emails.

Order confirmations & billing updates #

Sending money to companies over the internet requires trust. A prompt order confirmation email lets customers know their money didn’t disappear into a black hole.

If your company bills on a recurring basis, it’s a good idea to use transactional emails to keep customers updated. Billing update emails could let them know when a payment method has an error, when an account is canceled, or when renewal is coming up.

Image or Roark's order confirmation email.
Roark sends a transactional order confirmation right after a customer places an order.
Image of Google Domain's account payment reminder email.
Google Domains sends a triggered email when an account is 30-days out from renewal.

What does it mean to separate promotional and transactional email? #

Gmail officially suggests that "if you send both promotional mail and transactional mail relating to your organization, we recommend separating mail by purpose as much as possible." But what exactly does that look like?

Separating email types means you make sure your broadcast emails come from one source and your transactional from another.

Ideally, you’d have two separate sending infrastructures that include a unique IP address and subdomain. You wouldn’t want to take it as far as two entirely different domains since it could look like a phishing or spoofing attempt.

For example, you can ensure that broadcast and transactional traffic don’t mix by creating a Message Stream for each in Postmark:

Image of setting up different message streams in Postmark

Why you should separate promotional & transactional email sending #

Changing your workflow and sending setup can feel daunting, but here’s what you stand to gain once you invest in separating promotional from transactional messages.

Separating emails = better deliverability #

Deliverability matters.

Especially when you’re dealing with time-sensitive emails like password resets. But even broadcast messages need to make it to your customer’s inbox.

It's not always easy for email providers to categorize messages. By separating transactional and promotional emails, you remove the guessing game and make it easier for inbox providers to sort your emails. If you use the same servers and email address to send both broadcast and transactional email, filtering systems like Gmail's may classify it all as bulk email.

It also means that a sudden drop in your domain reputation from promotional emails won't jeopardize the deliverability of critical transactional messages.

Reduce support requests and improve brand trust #

Lost or delayed transactional emails lead to more "I tried to reset my password, but never got the email" support messages. Each one of those messages means more work for your team and a potentially damaged customer relationship.

By separating broadcast and transactional emails, you reduce support requests, give back more time to your team, and improve brand trust. It’s a win-win-win.

Managing and troubleshooting are easier

Transactional emails need speed, and broadcast emails don’t (as much). Broadcast emails benefit from routine list maintenance, and transactional emails need detailed troubleshooting. These two types of emails have their own goals, best practices, and issues.

By separating the two, you make it easier to optimize each without the other interfering.

How to separate promotional & transactional email sending #

So you’re curious about the details of separating your promotional and transactional emails. Where do you start? There are a few different ways to approach this challenge, with varying degrees of effort and impact.

Good: If you want to take a small step to divide up emails, you could try using different email addresses. For example, promotional emails would come from and transactional from However, given Gmail’s recommendation to use separate domains and IP addresses, merely using different email addresses should be a last resort.

Better: The next step up in separation would be messaging from different IP addresses. Many email providers let you set up a dedicated IP — usually at an extra cost — that you can use to separate your emails. But be aware that dedicated IPs aren’t a silver bullet for delivery, even though some providers will try to convince you otherwise.

These days, reputation focuses more on domains than IP addresses. This is because it’s much easier for spammers to burn through new IP addresses than to set up new domains.

So while using different IPs for your promotional and transactional email is an important step, you might want to go a step further.

Best: The best choice for fully separating your emails is to use different From addresses, IP addresses, and subdomains. For example, you might send your broadcast email from and your transactional email from If you need help warming up that new domain, we’ve got you covered here.

One promo email and one transactional email from Target highlight these best practices put to good use.
These two emails from Target highlight these best practices put to good use.

Postmark helps you separate your promotional and transactional email #

If you’re tired of managing two separate email infrastructures, Message Streams can make your life a whole lot easier.

For years, Postmark has been helping customers deliver lightning fast transactional emails. As products and customer needs evolved, we realized they needed help sending promotional emails with the same reliability.

That’s why we created Message Streams, an easy way to separate transactional from broadcast email sends. Thanks to parallel, but separate, sending infrastructures, we can help you get your promotional emails delivered while protecting the fast and reliable delivery of your transactional email. 

Here's a video on how Message Streams work in Postmark. This is one you donut want to miss 🍩

If you’re curious about sending promotional and transactional emails with Postmark, check out our Message Streams webinar or take Postmark for a spin with a free trial.

Steph Knapp

Steph Knapp

Write content, pet cats, eat pizza, repeat.