ESP Migration Guide for eCommerce Shops

Email service providers (ESPs) are essential for brands looking to invest in email marketing.

As your brand grows, you may find yourself outgrowing the capabilities of your current ESP. Choosing and subsequently migrating to a different ESP can be pretty tedious and carry some risks. However, if done correctly, it can set your brand up for more advanced email marketing tactics down the line and more robust growth.

Since there’s been a lot of buzz lately going around the Mailchimp & Shopify breakup, and lots of talk about ESP migrations, I created a post that outlines a general plan of attack with any ESP migration.

While I pull examples from different ESPs such as Klaviyo, the general framework should hold for all ESPs, even if the specific functionalities vary from platform to platform.

There are several categories of factors to consider when embarking upon migration, and I’ll be addressing each one of these core areas:

I also include an ESP Migration Checklist to help you cover all relevant points.

Let’s begin.

Moving ESPs will almost certainly cause fluctuations in your email deliverability. That said, if you are careful with implementing best practices, you can come out of the migration unscathed (or better yet, in better shape).

There are a host of deliverability house-keeping items you’ll definitely want to be aware of during a migration.

If possible, I recommend avoiding certain times of the year when planning an ESP migration. Particularly, the Q4 holiday season is a poor time to migrate. The inbox becomes very competitive during this time of year, and the inbox providers become more strict than usual with allowing incoming mail to be delivered. Introducing a wild card of an ESP migration isn’t usually a good idea, as it makes it harder for you to get ramped up and establish a solid sender reputation now than at other lower-volume times of the year.

Also, if you have certain big seasonal sales you normally run, try to avoid migrating immediately before those as well.

There’s a warmup period during the initial phases of migration that require a more restricted volume of email sends, and that could have a tangible negative impact on short term sales promotions.

The step of configuring your new sending infrastructure can be easily missed in the midst of the chaos of the migration. Yet, it’s an important step to implement in order to get your sender reputation off to a good start. Depending on if you are using a dedicated or shared IP address, the steps vary, but the most basic ones would include updating your SPF and DKIM records.

These are basically TXT records you add to your DNS in order for inbox providers to better identify your legitimate marketing emails are coming from you.

Some ESPs such as Klaviyo combine the authentication process through using CNAMEs to simultaneously white-label your domain, and offer additional customizations such as URL shortening and dedicated link tracking.

Regardless of your ESP, the important thing to note is that you will have to do some updates and configuration in order to get your new sending infrastructure set up correctly. Your ESP’s account manager and documentation should be very helpful in regards to the exact steps.

In order to ramp up your email list correctly on your new ESP, it’s best to institute a structured list onboarding process.

The reason you’d want to onboard in a disciplined manner instead of all at once, is because the inbox providers are generally more suspicious of emails sent from new infrastructure. It can be indicative of phishing, spoofing, and spam attempts.

As such, you’ll want to properly warm up the list so as to start off on the right foot deliverability-wise on your new ESP.

Also, an ESP migration is a great time to do some list cleaning in order to prune off dormant deadweight from your list.

Now that you have your shiny new ESP, you’ll need to make updates to the account settings, as well as integrations and templates. While some of the default settings can work well, chances are you’ll need to update at least some of them to meet your brand’s specific needs.

For those of you who are unfamiliar with the term, global frequency caps basically refers to a hard limit on the number of marketing emails a single subscriber can receive within a certain period of time. The purpose is to have a filter in place so that no single subscriber gets bombarded with too many emails, regardless of how many automated and/or campaign emails he or she might trigger in rapid succession.

Most ESPs have some sort of global frequency cap, though they may not allow you to configure it or override it selectively.

You should take a look at the options available and configure it according to what works best for your email marketing program. For example, Klaviyo (they call it “Smart Sending”) has a default setting of one email every 16 hours, which might be too conservative depending on your campaign cadence, resend frequency, and robustness of automated emails.

You may also want to selectively override the caps for certain automation. I normally override this for the Welcome email that delivers an incentive upon subscriber signup, as well as the first checkout abandonment email.

Chances are your new ESP will have its own mechanism for tracking revenue attribution. This can be a very useful feature for reporting and analysis, as well as triggering automated emails based on purchases from email.

That said, it’s not a bad idea to a) run Google Analytics (or other web analytics platforms) concurrently with the native ESP attribution and b) configure the attribution window to align with your own parameters.

Normally, ESPs will have a feature to allow you to append UTM parameters to all links within outgoing emails. This is superbly useful, as you don’t want to spend tedious hours tagging each link with these. Sometimes you can also configure the tracking parameters’ structure:

As for the attribution window, the default settings can often time be changed as well:

A simple point of configuration that might be easy to miss is your organizational settings. This is where you can usually configure your Company, Name, Address, Phone, Default From Address and Name, etc.

It’s a good idea to properly set these up since many templates would pull these values dynamically into the footer and other areas of your emails:

One mistake I see people making is having their personal info in the organizational settings, which incidentally pulls in that info into the marketing emails.

Configuring your opt-in and opt-out settings and pages are important to ensure a great user experience as well as to grow and retain your subscriber list.

For ESPs that have a List-level organizational structure, there may be an option to configure how unsubscribes to any particular list or email get treated, whether as a global unsubscribe or a local unsubscribe.

I normally like to set it by default to a global unsubscribe, but if you are maintaining specific lists for preferences, you could also go the other way… though I prefer using custom fields and variables to keep track of preferences instead of lists.

The default pages for unsubscribing and email preferences for most ESPs are pretty sparse and basic. Case in point:

If you want to apply any customizations to it, you’ll need to configure it yourself either using the default drag & drop editor or through editing the HTML source code.

Aside from branding/design changes, I recommend two other starting customizations:

1. Adding frequency preferences to your unsubscribe page to try and “save” a portion of potential unsubscribers.

2. Pull in only relevant preferences on the email preferences pages so that the form is not too overwhelming.

By default, many ESPs pass new subscribers through a double opt-in process, i.e. they have to further confirm via a link in their email before getting onto the list. While this is not always a bad idea, and indeed is required in certain jurisdictions, you may not want to have double opt-in by default and instead go for single opt-in.

In that case, you’ll want to configure your list settings accordingly. You may even need to email your ESP’s support directly to have them turn on the single opt-in functionality if it doesn’t exist already in your account.

Note that most of the time, manual CSV uploads will be single opt-in regardless of the settings of the particular list.

Most sites have some sort of email signup forms onsite. Common suspects are:

You’ll need to make sure all of these forms are now passing subscribers directly into your new ESP. For embedded forms on the site, such as a footer signup form, you can usually either a) swap out the code with the default embed code provided by your new ESP or b) change the hard-coded version’s action URL and list ID values to pass now to the new ESP’s URL & list:

Additionally, sometimes these footer forms pass directly into your shopping cart’s newsletter list, which can get automatically synced with your new ESP via a direct integration.

For the popup and flyout forms, if you use a third party software to power those, you can usually just swap out the integration directly inside that software. For example, inside Justuno, on the last setup page of each campaign, you can choose where to pass the subscribers to:

You’ll still want to make sure all incoming subscribers are directed to the correct lists inside your new ESP though.

In addition to other apps, you may decide to integrate with (loyalty apps, product review requests, recurring billing, shipping management, etc), the most important core integration for your new ESP will be with your shopping cart platform.

Enabling and configuring this integration is going to be key to power your email efforts moving forward given how much order-event data gets pulled through. Your ESP should have extensive documentation on the specifics on how to integrate with your shopping cart.

Here are a few random pointers to take into account though:

The first step in transitioning your existing automated emails and getting your new campaign emails into your new ESP is creating an updated email template. Whether you are using drag & drop or a custom HTML-coded template, you’ll need to create a new version inside your new ESP.

At the very least, you’ll need to incorporate the dynamic variables of your new ESP utilizing their new syntax.

For example, Mailchimp’s *|ARCHIVE|* becomes {% web_view %} in Klaviyo, and *|UNSUB|* becomes {% unsubscribe %}.

Per my note about deliverability and onboarding in the section above, it’s usually a good idea to get your automated marketing emails transitioned to your new ESP first before transitioning campaign emails (which you’ll need to warm up).

The general process we like to follow for moving the automated emails is:

A note about turning on/off automated sequences: if you have multiple emails within a sequence, oftentimes you’ll have contacts who are making their way through it still at the point you want to make the swap. In this case, one option you have is to implement a date filter at the initial trigger point of the old automation and keep both the new and old ones running simultaneously for a while, until which point the contacts in the existing automation all finish it. Then you can turn off the old automated sequence.

For example, for a welcome series it might look like this:

You can utilize this tactic in combination with back-population (if your ESP has it) to minimize the number of contacts who would otherwise have missed the emails in the automated sequences.

Generally speaking, we recommend keeping your transactional (like order/shipping confirmations) emails inside your native cart or app. If you do so, you can still do some customizations for branded design, as well as add some UTM tracking parameters to get more visibility into conversions.

Otherwise, if you do decide to move some transactional emails onto your new ESP, you’ll need to make sure it’s supported. Also, keep in mind that by default subscribers on your suppression list won’t get these emails − you’ll usually need to have your ESP turn on a special “transactional” designation for each individual email message so that those messages will override the suppression.

If you don’t do this, a handful of your customers who may have unsubscribed in the past to your marketing emails will end up not getting future transactional emails from you.

The best approach to transition your campaign emails is to follow some sort of onboarding plan to the new ESP.

It’s also best to stop sending from your old ESP entirely once you begin the campaign email transition process, because generally speaking, inbox providers don’t like seeing marketing emails from your brand coming from too many different sources and it can have adverse effects on your short-term deliverability.

I hope you found this helpful. Good luck with your present or future ESP migration. If you need professional help with it, contact us below.