Migrate from Mailchimp to Klaviyo



Klaviyo has a built-in integration with Mailchimp that will streamline the migration process as you move over from Mailchimp to Klaviyo. This is designed to be a one-time sync until you transition your data to Klaviyo. After you are completely transitioned to Klaviyo, we recommend that you remove your Mailchimp integration.

We also have a general checklist that covers how to completely migrate over to Klaviyo from a different email service provider (ESP) here.

We also have a recording of our Guided Walkthrough of Migrating from Mailchimp to Klaviyo if you'd like to watch a video of working through all the steps covered in this guide.


Migrating from Mailchimp to Klaviyo requires four key steps:

  1. Integrate your ecommerce platform with Klaviyo
  2. Integrate Mailchimp with Klaviyo
  3. Migrate your email templates from Mailchimp to Klaviyo
  4. Sunset your Mailchimp account

Integrate Your Ecommerce Platform with Klaviyo

Using Bigcommerce? Check out our guide to integrating Klaviyo with Bigcommerce.

Integrating your ecommerce platform with Klaviyo ensures that all you can leverage all your store’s data in Klaviyo to build segments, send emails, and more. We recommend completing this step before adding the Mailchimp integration.

Integrate Mailchimp with Klaviyo

Integrating your Mailchimp account with Klaviyo pulls over all of your contact data, including when contacts received, opened, and clicked emails.

First, you'll need to obtain a Mailchimp API key. We recommend creating a new key specifically for the Klaviyo integration, but you can use an existing key if you would like. You can get your Mailchimp API key by logging into Mailchimp, clicking your account name in the upper left, then navigating to Account > Extras > API keys.


Click Create a Key, then copy the key.


Once you've obtained your API key from Mailchimp, go into the Integrations tab of your Klaviyo account. Here, search for Mailchimp on the All Integrations list. Click Add Integration and paste in the Mailchimp API key.

Once you've pasted in your API key, review the advanced options. Check the first two options so you can sync all of your contacts' open and click data, along with all of your existing lists.

If you only want to sync specific lists, check the third option and specify the lists you want to sync by Mailchimp ID.

If you select Collect open and click data for Mailchimp campaigns AND Only sync specific lists, all contacts in your Mailchimp account will be imported into Klaviyo, regardless of whether or not they're in the specific lists you've chosen to sync. While syncing specific lists will recreate them in Klaviyo, it will not necessarily limit the number of contacts imported from Mailchimp.

After you click Connect to Mailchimp, data will start syncing over within a minute or two.

Review Your Mailchimp Data

Klaviyo pulls in the following data from Mailchimp:

  • When someone received, opened or clicked a particular email
  • Emails who have unsubscribed or bounced (these are added to your suppression list in Klaviyo)
  • Existing lists in Mailchimp
  • Contacts' Mailchimp Ratings
If a profile already exists in Klaviyo as an Active Profile before you add the Mailchimp integration, it will not be suppressed if it is suppressed in Mailchimp. For example, if you have a profile who is synced through your ecommerce integration before you add the Mailchimp integration, and this person unsubscribed in Mailchimp, they will not be suppressed in Klaviyo because they already exist as an Active Profile. To suppress these contacts, you can export them from Mailchimp as a CSV and upload them to your suppression list in Klaviyo. Only net-new unsubscribed contacts will be suppressed in Klaviyo with the integration.

Keep in mind that only names and email addresses of contacts will sync; to migrate over custom properties (tags) that may be attached to contact profiles in Mailchimp, see below.

If you delete a contact in Mailchimp, they will not be deleted in Klaviyo. However, if someone is added to a Mailchimp list, they'll be added to Klaviyo within an hour. We receive historical data from Mailchimp from the last 90 days; if you are syncing a large number of contacts from Mailchimp, this may differ.

The integration brings data over every 30 minutes for lists. For campaigns, it pulls data every 30 minutes on the first day and checks less frequently as time passes.

Mailchimp metrics are synced from campaigns that took place in the last 90 days. If a campaign is still sending, we will not sync the following metrics; these metrics will only sync for campaigns that are finished sending.

Clicked Email

The Mailchimp Clicked Email metric will track email click events synced from Mailchimp. To segment this metric further and see which contacts clicked which specific URLs in your emails, click on the Clicked Email metric in your Metrics tab and then use the advanced filters option to filter by URL.

Opened Email

The Mailchimp Opened Email metric will track email open events synced from Mailchimp.

Received Email

Klaviyo will sync a Mailchimp Received Email event every time someone successfully receives an email sent from Mailchimp (meaning the email was delivered to their inbox).

Import Mailchimp Tags into Klaviyo

If you use Mailchimp tags to label and organize your contacts, you can manually export and import these tags into Klaviyo. Klaviyo's built-in Mailchimp integration does not sync any of your tags.

Start by filtering your audience in Mailchimp by the specific tags you want to sync.

Next export your segment from Mailchimp. Use Mailchimp's guide for more information on exporting contacts with specific tags.

Once you've exported your data from Mailchimp you can import it into Klaviyo as custom properties. Custom properties get attached to your Klaviyo profiles, and you can create segments based off of specific properties, or use them to add filters to your flow or dynamically display data inside of your emails.

Migrate Your Email Templates from Mailchimp to Klaviyo

Klaviyo has an intuitive drag-and-drop template builder that you can use to recreate your Mailchimp templates. We recommend using this method to build your templates because it will ensure that they are mobile-optimized, responsive, and easy to edit and iterate on going forward.

However, if you don’t have time to dedicate to recreating your Mailchimp templates using Klaviyo’s template builder, it is possible to export your email templates from Mailchimp and import them into Klaviyo.

This process involves editing and updating the raw HTML of the email template. If you would instead like to use Klaviyo’s drag-and-drop editor to recreate your templates, check out our guide to learn the ropes of using Klaviyo’s template editor.

Export Your Template from Mailchimp 

In your Mailchimp account, navigate to the template that you would like to migrate to Klaviyo. In the dropdown beside the name of the template, select Export as HTML.


You will be prompted to save an HTML file to your computer.

Swap Out Template Tags

Klaviyo and Mailchimp use different template tags to insert dynamic content in your emails. For example, the “first name” tag is different in Mailchimp than it is in Klaviyo, so it’s important that you swap out any Mailchimp-specific tags with the corresponding Klaviyo tags.

The tag that is most important to swap out is the unsubscribe tag. Before you import your template into Klaviyo, you will have to add an {% unsubscribe %} tag because Klaviyo does not allow you to upload HTML templates that don't have unsubscribe tags unless they're for transactional emails.

To edit the tags in your template, open the HTML file in a text editor, like Sublime Text. Below is a table of other common Mailchimp tags and their corresponding Klaviyo tags.

Mailchimp Tag

Klaviyo Tag


{% unsubscribe %}


{{ first_name }}


{{ last_name }}


{{ organization.name }}


{{ email }}


{% manage_preferences %}


This is the subject line of the email, which is set on a per-email basis in the Klaviyo template editor.


This is the preview text of the email, which is set on a per-email basis in the Klaviyo template editor.

Learn more about template tags in Klaviyo.

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

Import Your Template into Klaviyo

In your Klaviyo account, navigate to the Email Templates tab and select Create Template. Then, select Import your Template. Here, you will be prompted to select the HTML file from your computer and you can upload the file you just saved.


You can see a preview of what your email template will look like in the Preview tab. Please note that going forward, you will have to directly edit the HTML in order to change the template. If you're interested in converting the template to a drag-and-drop template, you can follow these steps.

Sunset Your Mailchimp Account

If you begin deleting or cleaning contacts in Mailchimp before removing the integration, these contacts will be suppressed in Klaviyo. Once your Mailchimp account is safely sunsetted, be sure to remove the integration before deleting or cleaning contacts in Mailchimp that you don't want suppressed in Klaviyo.

After you've moved all your data over to Klaviyo, there are three key steps you can take to ensure that you no longer need your Mailchimp account:

  1. Ensure that your signup forms and list growth tools point to Klaviyo, not Mailchimp
  2. Recreate your automations as flows in Klaviyo
  3. Remove the Mailchimp integration

Signup Forms and List Growth Tools

If you have any signup forms or signup form campaigns in your Mailchimp account, you will want to ensure that these are recreated in Klaviyo so that your list continues to grow in Klaviyo rather than Mailchimp. You will not be able to redirect forms created in Mailchimp to Klaviyo. Instead, you can:

  1. Use the Klaviyo Signup Form Builder to re-create your forms from scratch
  2. Use a third-party list growth tool that integrates with Klaviyo
  3. Integrate your custom form through your ecommerce platform

If you are using a third-party list growth tool instead of Mailchimp's built-in form builder, make sure that this syncs to Klaviyo. Klaviyo integrates with a number of third-party list growth tools. Scan our list of integrations to find the tool that you're using. If you don't see it listed, consider using Klaviyo's native Signup Form Builder to create your forms, or switching to a different third-party tool.

Please note that all Klaviyo lists are double opt-in by default. If you would like to change a list to single opt-in and you are on a paid plan, please reach out to our Customer Success Team.

If you’re using a custom-coded form, there are two ways you can ensure that these contacts sync to Klaviyo. One option is to make sure that your custom form syncs new subscribers directly to your ecommerce platform and that your ecommerce store is integrated with your Klaviyo account. The second option is to point the form directly to your Klaviyo account by updating the Form Action URL. To find the Form Action URL in your Klaviyo account, go to your Lists & Segments tab and click on the list where you want to add your new subscribers. Click on the Subscribe Page tab and copy the URL from the right side of the screen.


After switching all your signup forms to point to Klaviyo, 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.

Next, you'll want to turn off your Mailchimp signup forms. To do that, head to the code of the page where you installed the form and remove the code that begins with

<!-- Begin Mailchimp Signup Form -->

and ends with 

<!--End mc_embed_signup-->

Email Automations

Klaviyo refers to email automations as flows and allows for much more advanced and targeted sequences. It is important to recreate these in Klaviyo so that you don't need to continue to use Mailchimp to send triggered emails.

As you move from Mailchimp, it may be a good time to refresh and update your automated messaging. The two flows we recommend that you turn live as soon as possible in Klaviyo are your Welcome Series and Abandoned Cart flows. A welcome series is particularly important to engage new subscribers, and abandoned cart flows have the highest ROI of any other type of flow.

Once your Klaviyo flows are live, you will want to turn off all of your automations in Mailchimp to ensure that you're not double-emailing people. To do this, click Edit in the dropdown on the automation email. Then, click Pause Sending.


Remove the Mailchimp Integration

Once you’ve pointed all of your list growth tools to your Klaviyo account, paused your Mailchimp automations, and turned your Klaviyo flows live, you can remove the Mailchimp integration. Before you remove your Mailchimp integration, make sure to double-check that everything is working as expected. Enter a test email into your signup form and other list growth tools, abandon a cart, and sign up for your newsletter to trigger a welcome series. Go to the Profiles tab in your Klaviyo account to make sure that the information in the profile reflects all of the correct communication. If the list you sign up to is double opt-in, be sure to confirm your email first.

Once you've taken these steps and are fully migrated to Klaviyo, you can go ahead and remove your Mailchimp integration. Click on the Integrations tab and select Settings under your Mailchimp integration. Select Remove in the upper right and confirm that you want to remove the integration.


Send Your First Campaign with Klaviyo

Once your Klaviyo account is integrated with your store and all of your data is ported over from Mailchimp, you can send your first campaign with Klaviyo. For deliverability reasons, we recommend sending to a highly engaged group of contacts for your first 4 weeks on Klaviyo. This will ensure that you start off on the right foot with Klaviyo and train inbox providers like Gmail, Yahoo, etc. to place your emails in the inbox.

Klaviyo pulls in contacts' "Mailchimp Ratings," which rate a contact's level of engagement on a scale of 1-5 stars. A contact with 5 stars is considered highly engaged, while a contact with only 1 star is considered unengaged.

To learn more about how Mailchimp Ratings are calculated, check out Mailchimp's documentation.

To send your first campaign, you must first build a segment of engaged subscribers. Klaviyo provides a default Engaged (3 Months) segment that will appear in the Lists & Segments tab. You can use this as a starting point, and then decrease the timeframe to 30 days and add historical Mailchimp engagement criteria to ensure that you’re reaching the right audience.


Once you have built this segment, you can go through the steps of creating and sending a campaign.

  1. Send exclusively to your "very engaged" segment for 4 weeks.
  2. Monitor your open rates using the Engagement Report.
  3. As your open rate increases above 20%, expand the timeframe conditions of this segment and continue to monitor open rates.


Below is a list of commonly used Mailchimp terms, along with their Klaviyo counterparts.

Mailchimp Term

Klaviyo Term


Flow: an automated sequence that is set in motion by a specific trigger and then includes one or more steps. Flows can be built to send emails to recipients, or they can simply apply certain actions; ex. abandoned cart, welcome series, updating a profile property.

Email Campaign

Campaign: a one-time email send to a list or segment of customers; ex. product launch or sale email.


Custom properties: custom values that can be added to contacts’ profiles and are available to use in segments and flows; ex. gender, birthday, product interest.

Advanced Segment

Segment: a dynamic group of people constrained by a set of conditions. Segments do not need to be based on a particular list; ex. anyone who purchased more than 6 months ago and hasn’t purchased since. Regardless of your subscription plan, you can use this feature to add a large number of different conditions.

Signup Form Campaign

Signup form: an embedded, popup, or flyout email and data collection tool.

Ad Campaign

Facebook Advertising Integration: an integration between Klaviyo and Facebook that allows you to display targeted ads to audiences on Facebook and Instagram.

Cleaned Contacts

Suppressed profiles: contacts who have unsubscribed, marked an email as spam, hard bounced, or have been manually suppressed. It is not possible to email these contacts.


If I delete people in Mailchimp, are they deleted in Klaviyo? 

If I unsubscribe someone in Mailchimp, are they unsubscribed in Klaviyo? 
Yes. If someone is suppressed in just one Mailchimp audience, they will be suppressed globally in Klaviyo. However, this only applies to net-new contacts. Contacts who were already synced through another integration (i.e. your ecommerce integration), will not be suppressed even if they have unsubscribed in Mailchimp. To suppress these contacts, you can export them from Mailchimp as a CSV and upload them to your suppression list in Klaviyo.

If I unsubscribe someone in Klaviyo, are they unsubscribed in Mailchimp? 

If I add someone to a list in Mailchimp, are they added to a list in Klaviyo?
Yes, after 15 minutes if the address has status "subscribed" or "unsubscribed".  If the email address in Mailchimp is in status "pending" (added with double opt-in, but has not yet confirmed their subscription) or "cleaned" (the address bounced and was removed from the list), they will not be synced to Klaviyo.  When an address confirms their subscription, they will move from "pending" to "subscribed" in Mailchimp and will be synced to Klaviyo in the next periodic sync.

If I add someone to a list in Klaviyo, are they added to a list in Mailchimp?

How often does my Mailchimp data sync with Klaviyo?
Your lists will sync every 30 minutes and your unsubscribes, opens, and clicks will sync every 30 minutes on the first day of your integration and will sync less frequently with time as you should be migrated over after your first few days.

How often will my Shopify store orders sync with Klaviyo?
Orders sync with Klaviyo in real time.

How often will my Bigcommerce store orders sync with Klaviyo?
Orders sync with Klaviyo in real time.

Does the integration pull all of my campaign history?
Klaviyo syncs the last 90 days of campaign history. This is sufficient data for building a list with good engagement criteria

Why should a company keep Mailchimp and Klaviyo? Why not fully commit to Klaviyo and import everything into it?
We recommend switching over fully to Klaviyo. You can start by integrating with Mailchimp. Next, check out the key guidelines outlined here.

Does Klaviyo offer something similar to the Mailchimp rating?
We do not currently offer something equivalent to a Mailchimp rating. Instead, you can use Klaviyo’s segmentation builder to create an engaged segment that matches your specific definition of engaged.

Was this article helpful?
128 out of 144 found this helpful