Is it a bad idea to use two services for delivering an email from your app, like SendGrid for transactions and Mailchimp for marketing emails?
Generally speaking, there are primary considerations: price, data, and deliverability.
Price
Price is a factor, especially if you’re sending (or are going to send) considerably more email volume through transactions than to the actual opt-in email marketing audience. Splitting transactional emails out into their own system allows you to take advantage of simple MTAs/Transactional Email Services like SendGrid/Mailgun/Postmark and get better price per email, while simultaneously leveraging the getting the added benefits of a marketing suite that comes with Mailchimp/Klaviyo/ActiveCampaign for your marketing emails (drag and drop builders, workflow capabilities, customer journey and behavior tracking, etc).
Most marketing email service providers like Mailchimp, Klaviyo, and ActiveCampaign charge on a per contact basis, and thus even though they may support transactional emails, you may end up having a large cohort of email addresses in your database that receive transactional emails, but nothing else. Despite that, some do offer pricing on a per email sent basis, which you should talk to an account manager and see if it makes sense for your needs.
Data
The downside of setting up a separate platform for transactional and marketing emails comes when you may need to leverage data from one system from another. If you want to trigger marketing content based on the engagement with transactional emails, you’ll need to ensure that data makes it to your marketing ESP. While this may not seem like a common use case, if you send email and communication upon an app or platform registration verification process, you’ll need to pass that information to your marketing focused ESP for a couple of reasons. First, any bad contacts like bounces, fake addresses will need to be cleaned, and you can rely on your transactional system reporting to send that info to your marketing ESP. Next, if users don’t in fact engage with your transactional emails, you may need to send them a reminder nudge, and in a lot of cases this is better handled by the marketing ESP.
The other thing to consider is that you’ll also be doubling up on the integration with your ecommerce platform or application because it has to be connected with both a transactional service, and your email marketing/marketing. Depending on whether or not the platforms have native integrations, this may or may not be a big deal.
Deliverability
The final consideration should be made on deliverability. By splitting those emails between two different systems, it also means they’ll be delivered on separate IP addresses. There are two sides to this coin.
On one hand, having your transactional emails on their own domain and IP address all but ensures they’ll hit the inbox, as most transactional ESPs are focused on just that, and thus (generally speaking) have better IP reputations, while leaving marketing emails to a separate IP address pool (often shared with other marketing emails from other brands) means you don’t get the added bump of transactional emails.
On the other hand, having them lumped together could be bad if most of the volume of email you do is marketing (and with low engagement). You could run into a situation if you’re not careful where your transactional emails don’t hit the inbox.
It’s best to consult with an expert for your specific needs to make the best and most informed decision on which path to go down.
Need an email marketing experts’ opinion on your use case?
Let’s chat.