How to Migrate from Mailchimp to Klaviyo – Everything you need to know

Ryan Turner // August 12 // 0 Comments

Ready to make the transition from Mailchimp to Klaviyo? Congrats! This is likely a great decision and one we recommend to almost all Ecommerce brands currently using Mailchimp.

In this guide we’ll walk you through the process step-by-step so you don’t miss anything. Migrating to Klaviyo from Mailchimp may seem daunting at first, but the process is actually fairly simple. If you’re not quite sold on Klaviyo yet, check out our detailed Klaviyo review to see why we love the platform so much.

Here’s what we’ll cover in this guide:

Migrating from Mailchimp to Klaviyo: Where should you start?

The first thing you need to do is simply sign up for a new Klaviyo account. Then you will need to integrate your Shopify store with Klaviyo, Integrate Mailchimp with the Klaviyo account, and you’re done. We’ll show you how to do each of those steps in this guide.

When you first set out to migrate your emails, it is important to cleanse and update your current mailing list in Mailchimp first. And, before you do anything else, you should remove subscribers who haven’t opened your emails in months. If people are not interested in hearing from you – just remove them. Using a new email platform won’t make any difference, and migrating between softwares gives you a good opportunity to clean house, and save a little on your Klaviyo cost.

To prevent old Mailchimp email campaigns from migrating over to Klaviyo, it’s best to pause your scheduled emails before starting the process.

Be sure to preserve your Mailchimp account by not deleting it. You’ll need to keep your Mailchimp account running for a period of time for Klaviyo’s integration to work correctly. In order to retrieve certain bits of information, you’ll need to access the account. Keep your account active until you have transferred all of your data and ensured that Klaviyo is fully operational.

Now, you’re ready to start moving over to Klaviyo!

Moving your data

First things first, make sure your Ecommerce platform (the platform you use for your online store) is no longer connected with Mailchimp before you start moving your data. Now that Klaviyo is integrated you want all of your customer data and interactions to go into their software instead.

Klaviyo & Mailchimp Integration via Mailchimp API key

Connecting your Mailchimp account to Klaviyo brings over all your contact data. This includes not only your email contacts but also data points around engagement such as when people opened, clicked, and when they first became your contacts. Klaviyo can read a quite a lot of Mailchimp stats, so you won’t be starting from scratch trying to work out which contacts are engaged and which aren’t.

To start, we recommend that you create a new API key specifically for this Klaviyo integration.

Follow these steps to retrieve your Mailchimp API key: Log into Mailchimp, find your account name in the bottom left corner, and go to Account > Extras > API keys.

Setting up a Mailchimp API key for Klaviyo
Setting up a Mailchimp API key for Klaviyo

Then just click Create Key and copy it! As simple as that.

API key section in Mailchimp
API key section in Mailchimp

Now go into your Klaviyo account’s Integrations tab once you’ve obtained your Mailchimp API key. There you can search for Mailchimp in the All Integrations list.

Once you find it, add the integration and paste the Mailchimp API key you’ve copied. 

Mailchimp integration screen in Klaviyo
Mailchimp integration screen in Klaviyo

After that, choose advanced Options:

  • Collect click and open data for Mailchimp campaigns (select this option to sync MailChimp engagement)
  • Create Klaviyo lists from Mailchimp lists (select this option to sync all your lists from existing Mailchimp lists)
  • Only sync specific lists – (select this option to only sync specific MailChimp lists – After that, you can choose which lists you want to sync).

If you have a lot of different lists in Mailchimp, some of which you don’t use or need, we highly recommend cleaning up your account in Mailchimp first before migrating. Get clear on exactly which lists you want to use going forward, and import only those lists into Klaviyo.

Now click Connect to Mailchimp, and your data will begin syncing.

Sync Frequency

After you establish the integration, Mailchimp data syncs to Klaviyo as follows:

  • Existing lists sync every 30 minutes.
  • Existing campaigns sync every hour.
  • Every 6 hours, Klaviyo checks for new lists and campaigns. Once a new list or campaign is identified, they will sync every 30 minutes or 1 hour, respectively.

Pro Tip From Klaviyo:

When you review Mailchimp documentation, keep in mind that Mailchimp now refers to “lists” as “audiences”. A customer’s engagement data in Mailchimp is tied to the Mailchimp audience they were part of when they received a campaign.

If you move a customer to a different Mailchimp audience after they receive a campaign, the engagement data for that customer will not follow the customer to the new audience. This means that Mailchimp engagement data may not be complete if you switch your customer from their original audience to a different audience after they’ve received a Mailchimp campaign.

If you select Only sync contacts from specific audiences in Advanced Settings, you’ll need to designate all the Audience IDs to which campaigns were previously sent. Even if a different synced audience contains the same contact, if a campaign was not originally sent to that audience, you will not see complete engagement data for that campaign.

Klaviyo will only sync campaigns with the “Sent” status. Campaigns with the “Sending” status will not be synced.

Take a look at your Mailchimp data


Data Klaviyo pulls in the following information from Mailchimp:

  • When someone receives, opens, or clicks on a particular email
  • When someone subscribes to a Mailchimp list 
  • People that have been unsubscribed or bounced will be added to your suppression list in Klaviyo
  • Lists that already exist in Mailchimp Contacts, and Mailchimp Ratings

The profiles in Klaviyo that already exist as Active Profiles, before you added Mailchimp integration, will NOT be suppressed if they have already been suppressed in Mailchimp.

These contacts can be exported from Mailchimp as CSV files and imported to a suppression list in Klaviyo. That’s important because it keeps your email lists healthy and increases your sender reputation.

Importing your Mailchimp tags into Klaviyo

Are you using Mailchimp tags? Then follow these steps.

Mailchimp tags are used for labeling and organizing your contacts and must be imported manually into Klaviyo. 

First go to your Mailchimp account and find your tags. Then export them as a CSV file and simply import them into Klaviyo as custom properties.

Start by exporting them from Mailchimp as a CSV and uploading them to your Klaviyo account as custom properties.

Exporting Mailchimp contact data
Exporting Mailchimp contact data

Some examples of custom properties that you may want to add to your Klaviyo profiles are:

  • Preferences around what kind of content subscribers would like to see or how often they would like to receive emails
  • Subscriber birthdays
  • Subscriber geographic regions

Custom properties are parameters that are used to create specific segments and filters in your flows. They are pretty useful, so don’t skip this step if you want to be as granular as possible in your Klaviyo campaigns.

Moving Mailchimp Email Templates To Klaviyo

You can count on Klaviyo to make it as simple as possible to design and build the perfect email templates that are sure to engage your audience on both desktop and mobile.

If you already have Mailchimp emails as HTML files, you can export the HTML and upload them to Klaviyo, but you will first need to update the template tags as Klaviyo will not upload an HTML file with an incorrect tag.

Mailchimp HTML templates
Mailchimp HTML templates

Klaviyo only allows email templates that include the unsubscribe tags to be uploaded to the platform. It is essential that you use the proper unsubscribe tag. Every email has to have it. Before importing your template into Klaviyo, you’ll need to add a tag: {% unsubscribe %}.

Be sure to see this chart of common Mailchimp tags and their Klaviyo counterparts. You’ll need these if you plan to upload Mailchimp HTML templates to Klaviyo’s platform.

Once you’ve swapped out the tags for Klaviyo tags, you can save your HTML file.

Learn more about template tags from Klaviyo.

Recreate your email marketing system in Klaviyo

Now that you no longer use your Mailchimp automations, it is time to recreate them as Klaviyo flows and then turn them off in Mailchimp. This will prevent you from sending emails to your audience twice.

When you finished the data migration, it hopefully pulled in the engagement ratings of your contacts.

The ratings are given on a scale of 1 to 5 – subscribers with a rating of 5 are highly engaged, while those with a rating of 1 aren’t engaged at all.

You’ll need to build a segment of engaged subscribers in Klaviyo before sending your first email. You can create your segments under Lists & Segments.

Say goodbye to your Mailchimp account

Once all your data has been moved to Klaviyo, you can follow three steps to make sure that you no longer need your Mailchimp account.

  • Step 1: Make sure that your signup forms and list growth tools point to Klaviyo, recreate your automations as flows in Klaviyo, remove the Mailchimp integration. Just like that, you have successfully transferred to Klaviyo.
  • Step 2: Once you’ve pointed all of your list growth tools to Klaviyo, paused your Mailchimp automations, and turned your Klaviyo flows live, you can remove the Mailchimp integration.
  • Step 3: Before you remove your Mailchimp integration, make sure to double-check that everything is working as expected. This includes doing a few test-signups yourself and making sure all the data is coming into Klaviyo correctly.

A tip to remember: keep your Mailchimp account active until the very end. You can delete it once you’ve migrated all of your data and confirmed that everything in Klaviyo functions as you want. Implement this when you are transferring to other email service providers.

Mailchimp Signup Forms

Mailchimp signup forms cannot be redirected to Klaviyo, so you’ll want to recreate them in Klaviyo if you have any. Alternatively, integrate a third-party list-growth tool such as Privy or JustUno, or integrate a custom form from your Ecommerce platform.

We do however like the Klaviyo forms and popups for list building and generating new email leads from website traffic.

Klaviyo signup form templates
Klaviyo signup form templates

Once you’ve re-created all your signup forms, wait a few days and watch your lists in Mailchimp. If you notice subscribers are still being added to these lists, there’s probably at least one form that still needs to be swapped out.

Now that you’re confident that your signup forms have all been moved correctly, it’s time to turn off the ones from your Mailchimp account. In order to do that, go to the code of the page where you installed the form and just remove the code that starts with:

Mailchimp signup form script
Mailchimp signup form script

Start setting up Flows in Klaviyo

As soon as you have fully configured your Klaviyo account, we recommend setting up a series of flows to contact your customers during different stages of the purchasing process, including integrating with additional platforms and launching testing and reporting as soon as possible. This is not Mailchimp, so you will be creating email flows not automations – which are basically the same thing, just named differently.

Also, Klaviyo has recently launched the Reports Library with pre-built reports that analyze data, growth, and revenue. So make sure you check it out.

Let us get back to the flows.

Here are some of the most important Ecommerce email marketing flows every business should have setup:

There are lots more flows than this of course, Klaviyo provides endless built-in flow options. But these are some of the basics.

Some of Klaviyo's built in automations
Some of Klaviyo’s built in automations

Tip – See which of your favorite Ecommerce tools have Klaviyo integrations. Often you’ll be able to setup custom flows based on those too.

Sending your first campaign

To ensure a better chance of your messages arriving in inboxes for the first few weeks on Klaviyo, we recommend sending a single email campaign to a highly engaged group of contacts.

This is where segmentation comes into place. Create an Engagement segment – this segment will have people that are most engaged with your website, so they are more likely to open your email.

Klaviyo engaged segment example
Klaviyo engaged segment example

As a starting point, Klaviyo provides the Engaged (3 Months) segment in the Lists & Segments section. We like to move this to a 30 day engaged window for new accounts for the first few weeks until you’re consistently seeing high open rates.

Remove The Mailchimp integration

Once you’ve configured your Klaviyo account, stopped the Mailchimp email campaigns, and created new Klaviyo flows and campaigns, you can deactivate the Mailchimp integration.

When you’ve taken these steps and fully migrated to Klaviyo, go ahead and delete your Mailchimp integration.

Just click on the Integrations tab and look for the Settings button in your Mailchimp integration. You’ll need to select the ‘Remove’ button in the upper right and confirm that you want to remove the integration.

Congratulations: You’re done!

You have successfully managed to migrate from Mailchimp to Klaviyo.

Hopefully, now you can continue your email marketing with Klaviyo, while still using your Mailchimp templates and contacts. If you want to take the next step and become a true Klaviyo expert, take a look at our Ecommerce email training program which shows you how to use the software in-depth.

And if you just don’t have time or want everything done-for-you, get in touch and ask about our Klaviyo agency services specifically for Ecommerce brands. We’ll even migrate you over to Mailchimp without any additional cost as part of our regular services.

About the Author Ryan Turner

Ryan Turner is the lead strategist here at EcommerceIntelligence.com with over 6 years experience growing Ecommerce brands using proven Klaviyo email marketing strategies.