How to Migrate from Mailchimp to Klaviyo: Step-by-Step Guide

How to Migrate from Mailchimp to Klaviyo: Step-by-Step Guide

Migrating from Mailchimp to Klaviyo is one of the most common email platform switches for eCommerce brands in 2026 — and for good reason. As Mailchimp's pricing has climbed and its core features have stagnated relative to commerce-native competitors, Klaviyo has emerged as the clear default for Shopify, WooCommerce, and DTC brands that need advanced segmentation, behaviour-based automation, and revenue-attributed reporting built for online retail.

The migration is less painful than most brands expect — and more work than vendors want you to believe. This guide gives you the complete, honest picture: what transfers automatically, what needs rebuilding, how long it actually takes, and how to execute a clean cutover without dropping a single subscriber or triggering a deliverability problem.

The migration involves five core stages: audit and clean, connect and sync, rebuild flows and templates, authenticate your domain, and cut over with a warm-up plan. Do them in order and you will be fully live on Klaviyo within two to four weeks.

Why Brands Migrate from Mailchimp to Klaviyo

Before the how, the why matters — because it shapes what you prioritise in the migration.

The most common reasons brands make this switch are advanced eCommerce segmentation, pricing at scale, and automation access. Mailchimp's segmentation is functional for basic list filters but does not support the real-time, behaviour-based segments that power Klaviyo's most effective campaigns — segments that update automatically as customer behaviour changes, without manual intervention. Klaviyo's abandoned cart, post-purchase, and win-back flows are purpose-built for eCommerce in a way Mailchimp's are not.

On pricing, Mailchimp charges per contact stored — including unsubscribed contacts — and its pricing climbs quickly as lists grow. Klaviyo charges only on active marketing profiles and gives you access to core automation features from its free plan, while Mailchimp restricts advanced automation to paid tiers.

Klaviyo is also the highest-rated email platform on the Shopify App Store, with more reviews and higher ratings than Mailchimp for eCommerce merchants. If your store runs on Shopify, the native Klaviyo integration is one of the most seamless in the ecosystem.

What Transfers Automatically vs What Needs Rebuilding

Before starting, know exactly what migrates and what you need to recreate.

What transfers via Klaviyo's native Mailchimp integration:

• All subscriber information including email addresses, names, and custom fields
• Mailchimp audience lists — synced as Klaviyo lists
• Subscription and unsubscribe statuses
• Email engagement history — opens, clicks, and receives from the last 90 days
• Mailchimp contact ratings and tags
• Cleaned and bounced contacts — synced as suppressed profiles in Klaviyo

What you need to rebuild manually:

• Email automation flows — Mailchimp automations do not transfer; you recreate logic in Klaviyo's flow builder
• Email templates — HTML templates can be imported but are best rebuilt in Klaviyo's native drag-and-drop editor for mobile optimisation and Klaviyo-native dynamic content
• Signup forms and pop-ups — all website forms must be replaced with Klaviyo forms
• Segments — recreated in Klaviyo using imported contact data and behaviour signals
• Campaign history beyond 90 days — historical send data does not transfer; download and save it from Mailchimp for reference

Understanding this split prevents the most common migration disappointment — expecting automations and templates to come across automatically when they require active rebuilding.

Step 1: Audit and Document Your Mailchimp Account

Before touching any settings in either platform, document everything you currently have in Mailchimp. This is the step most brands skip and the one that causes the most problems later.

Create a simple spreadsheet and list every active automation with the trigger, the number of emails in the sequence, and the send conditions. Screenshot every form and popup on your website. List every audience segment you actively use. Export your campaign history and performance data for reference — open rates, click rates, and revenue attribution from your best campaigns are benchmarks you will want to compare against once you are live on Klaviyo.

This audit typically takes two to four hours depending on account complexity. It is time well spent because it becomes your rebuild checklist for Step 4.

Also take this opportunity to clean your list. Remove subscribers who have not opened a single email in the last 12 months. Correct obvious data errors in custom fields. Klaviyo's deliverability depends on sending to engaged profiles, and importing a dirty list will damage your reputation on the new platform from day one. Most email agencies recommend importing only contacts who have engaged in the last 90 to 180 days for your initial sends, with a separate suppression list for older unengaged contacts.

Step 2: Set Up Your Klaviyo Account and Connect Your eCommerce Store

Sign up for Klaviyo and complete the initial account setup before doing anything else with your Mailchimp data.

If you are on Shopify: Go to the Klaviyo app listing in the Shopify App Store and install it directly. Klaviyo will immediately begin syncing your customer purchase history, product catalogue data, and live cart events. This eCommerce data is what makes Klaviyo's segmentation and flows work — it must be connected before you import contacts so that historical purchase data is matched to the right profiles.

If you are on WooCommerce: Install the official Klaviyo WooCommerce plugin from the WordPress plugin directory. Authenticate with your Klaviyo API key and configure the events you want to track — placed order, viewed product, added to cart, started checkout.

If you are on Magento or BigCommerce: Use the native integrations available in Klaviyo's integrations library. Both require API key authentication and event configuration, but the process is well-documented and typically takes under an hour.

Important for Shopify users: If Mailchimp is currently connected to your Shopify store, disconnect it before connecting Klaviyo. Running both integrations simultaneously can trigger double opt-in emails to your existing subscriber list. Disconnect the Mailchimp-Shopify integration first, then connect Klaviyo.

Step 3: Connect Mailchimp and Sync Your Contacts

Klaviyo has a native Mailchimp integration that handles the contact data sync automatically.

In your Klaviyo account, go to the Integrations tab and click Explore apps. Search for Mailchimp and click Install. You will need your Mailchimp API key — generate a new one from Mailchimp's Account and Billing settings under Extras, then API keys. Paste the key into Klaviyo's Mailchimp integration setup.

Once connected, Klaviyo will sync all of your Mailchimp audiences as Klaviyo lists, including subscription statuses, engagement data from the last 90 days, contact ratings, and tags. For large lists this sync can take several hours — this is normal. Do not try to manually import contacts simultaneously or you will create duplicate profiles.

After the sync completes, verify in Klaviyo's Lists and Segments section that your audience counts match what you had in Mailchimp. Check a sample of individual profiles to confirm that custom fields, tags, and subscription statuses transferred correctly.

Unsubscribed and cleaned contacts from Mailchimp will appear as suppressed profiles in Klaviyo — this is correct behaviour and ensures you do not accidentally email contacts who have opted out.

Step 4: Rebuild Your Email Flows

This is the most time-intensive part of the migration and cannot be automated. Mailchimp automation sequences do not transfer — you recreate the logic in Klaviyo's flow builder.

The good news is that rebuilding in Klaviyo is faster than building from scratch because you have your audit documentation from Step 1. The better news is that Klaviyo's flow library includes pre-built templates for every major eCommerce automation — you are not starting from a blank canvas.

Priority flows to rebuild first:

Abandoned cart flow — This is your highest-revenue automation. In Klaviyo, create a new flow and select the "Started Checkout" trigger (Shopify) or your equivalent cart abandonment event. Add a time delay of one hour before the first email, then 24 hours before a follow-up. Connect your eCommerce integration to pull in the abandoned product details dynamically.

Welcome series — Triggered by the "Joined List" event on your main email list. Typically three to five emails over the first seven to fourteen days after signup. Recreate the email content and timing from your Mailchimp welcome sequence.

Post-purchase flow — Triggered by the "Placed Order" event. Usually begins twenty-four to forty-eight hours after purchase with a review request or related product recommendation. Klaviyo's post-purchase flow templates include dynamic product blocks that pull from your store catalogue automatically.

Win-back flow — Triggered by a segment of customers who purchased but have not engaged in a defined window (typically 90 to 180 days). This is where Klaviyo's predictive analytics add value that Mailchimp cannot replicate — you can target users with elevated churn risk scores automatically.

For email templates, import your Mailchimp HTML files into Klaviyo's template editor as a starting point — go to Email Templates, click Create Template, and choose Import from HTML. For most brands, rebuilding the template natively in Klaviyo's drag-and-drop editor is worth the extra hour — it ensures mobile responsiveness, Klaviyo-native dynamic blocks, and access to personalisation tokens specific to Klaviyo's data model.

Keep all rebuilt flows in draft or paused state until Step 6. Nothing should be sending from Klaviyo while Mailchimp is still your primary platform.

Step 5: Set Up Domain Authentication

Domain authentication is non-negotiable. Skipping it will damage your deliverability from the first send.

In Klaviyo, go to Account Settings and then Email. Click on your sending domain and follow the DNS record setup instructions. You will need to add the following records to your domain's DNS settings through your domain registrar:

SPF record — Authorises Klaviyo's servers to send email on behalf of your domain. Klaviyo will provide the exact TXT record value to add.

DKIM record — Cryptographically signs your emails to verify they come from your domain. Klaviyo generates two CNAME records you add to your DNS.

DMARC record — Instructs receiving mail servers what to do with emails that fail SPF or DKIM checks. Start with a monitoring-only policy (p=none) and tighten it after your first month of clean sending.

DNS changes typically propagate within a few hours but can take up to 48 hours to fully resolve. After adding the records, use Klaviyo's built-in verification tool to confirm authentication is working before sending your first campaign.

Also update your sending name and from address in Klaviyo to match what subscribers recognise from your Mailchimp emails. Consistency here reduces unsubscribe rates on your first sends.

Step 6: Replace Website Forms and Test Everything

Before cutting over from Mailchimp to Klaviyo, every signup form on your website must be pointing to Klaviyo instead of Mailchimp. This includes embedded newsletter forms, footer forms, pop-ups, checkout opt-ins, and any third-party form tools (Typeform, Gravity Forms, and similar) that currently send subscribers to Mailchimp.

In Klaviyo, go to the Forms section and recreate or build new versions of your Mailchimp forms. Klaviyo's form builder supports embedded forms, pop-ups, and flyout banners with targeting rules for new versus returning visitors, exit intent, and time on page.

Once your forms are live and pointing to Klaviyo, run a thorough test:

• Enter a test email into your website signup form and confirm the profile appears in Klaviyo
• Add a product to your cart and abandon it — confirm the "Started Checkout" event fires in Klaviyo's activity feed
• Place a test order — confirm the "Placed Order" event appears and triggers your post-purchase flow correctly
• Click through from a test email and verify that UTM tracking parameters are working correctly for revenue attribution

Run both platforms in parallel for three to seven days at this stage — Mailchimp stays active but paused, Klaviyo is active with forms live and flows ready to launch. This parallel period lets you catch any issues before fully committing to Klaviyo.

Step 7: Warm Up Your Domain and Go Live

Do not blast your full list from Klaviyo on day one. This is the step most brands underestimate and the one that causes deliverability problems.

Gmail, Outlook, and Yahoo need to learn that your domain sends high-quality, wanted email. A sudden volume spike from a new sending infrastructure triggers spam filters regardless of how clean your list is.

Week 1: Send to your most engaged 10–20% of subscribers — people who have opened an email in the last 30 days. Start with a simple campaign rather than turning on all your flows at once.

Week 2: Expand to subscribers who have opened in the last 60–90 days. Turn on your welcome series and abandoned cart flow.

Week 3: Full list sending and all remaining flows active.

Monitor your deliverability metrics in Klaviyo throughout the warm-up. Keep your bounce rate below 2% and your spam complaint rate below 0.08%. If either climbs above these thresholds, pause and clean your list further before continuing.

Once your domain is fully warmed and all flows are confirmed working, remove the Mailchimp integration from Klaviyo. Important: remove the integration before cleaning any contacts in Mailchimp. If you clean contacts in Mailchimp while the integration is still active, those contacts will be suppressed in Klaviyo — which may not be your intention for contacts you want to keep.

Timeline: How Long Does This Migration Take?

For brands with simple setups — one or two flows, a few email templates, and a small list — two weeks is realistic. For brands with complex automation sequences, large contact databases, and multiple audience segments, four weeks is the safer target.

Common Mistakes to Avoid

Importing your full list without cleaning it first. Sending to unengaged contacts from a new platform is the fastest way to damage your Klaviyo domain reputation. Clean before you import.

Disconnecting Mailchimp before Klaviyo is fully tested. Run both in parallel until you are confident Klaviyo is working correctly. There is no reason to turn off Mailchimp until Klaviyo has been validated.

Skipping domain authentication. Even if your emails land in inboxes initially, unauthenticated sending will cause deliverability problems as inbox providers tighten their requirements. Set up SPF, DKIM, and DMARC before your first send.

Turning all flows on simultaneously. Turn on flows gradually during your warm-up period. A sudden spike from multiple flows triggering at once is harder to manage than a controlled rollout.

Not updating all website forms. A form left pointing to Mailchimp means new subscribers are not making it into Klaviyo. Audit every form on your site — including checkout opt-ins and third-party tools.

Conclusion

Migrating from Mailchimp to Klaviyo is one of the highest-ROI technology decisions an eCommerce brand can make in 2026. The segmentation depth, eCommerce-native automation, and revenue attribution that Klaviyo delivers natively require workarounds and expensive add-ons to replicate in Mailchimp.

The migration itself is manageable — plan two to four weeks, follow the steps in order, do not skip domain authentication, and warm up your domain properly. Brands that do this correctly are typically seeing Klaviyo's advanced flows generate meaningful revenue within the first 30 days.

Need Help with Your Migration?

Rackwave is a certified Klaviyo implementation and account management partner. We serve clients across the USA, UK, Canada, Australia, and Singapore — managing Mailchimp-to-Klaviyo migrations with zero campaign downtime and full data integrity.

Whether you need a fully managed migration, a post-migration audit, or ongoing Klaviyo campaign management — our certified team delivers it.

Explore Our Klaviyo Migration Services →

Frequently Asked Questions

How long does it take to migrate from Mailchimp to Klaviyo?
Most eCommerce brands complete the migration in two to four weeks. Simple setups with a small list and one or two flows can be done in under two weeks. Complex accounts with many automation sequences, large contact databases, and multiple segments should plan for four weeks including the domain warm-up period.

Do my Mailchimp contacts transfer automatically to Klaviyo?
Yes. Klaviyo's native Mailchimp integration syncs all subscriber data automatically — including email addresses, names, custom fields, subscription statuses, unsubscribes, and engagement history from the last 90 days. You do not need to manually export and import your contacts if you use the native integration.

Do Mailchimp automations transfer to Klaviyo?
No. Mailchimp automation sequences do not transfer to Klaviyo. You need to recreate your automation logic as Klaviyo flows using the flow builder. The triggers and email content do not carry over — you rebuild them using Klaviyo's pre-built flow templates as a starting point.

Will I lose my email open and click history from Mailchimp?
Klaviyo syncs engagement history from the last 90 days via the Mailchimp integration — opens, clicks, and email receives. Engagement data older than 90 days does not transfer. Download your full campaign history from Mailchimp and save it for reference before completing the migration.

What happens to unsubscribed contacts during migration?
Unsubscribed and cleaned contacts from Mailchimp are synced to Klaviyo as suppressed profiles. This ensures you cannot accidentally email people who have opted out. Do not clean contacts in Mailchimp while the Klaviyo integration is still active — cleaning in Mailchimp will suppress those contacts in Klaviyo as well.

Do I need to set up domain authentication in Klaviyo?
Yes — this is essential and cannot be skipped. You need to add SPF, DKIM, and DMARC records to your domain's DNS settings before sending from Klaviyo. Unauthenticated sending damages deliverability. Klaviyo provides the exact DNS values in your account settings under Email.

Can I run Mailchimp and Klaviyo at the same time during migration?
Yes — and you should. Running both platforms in parallel for three to seven days after Klaviyo is set up lets you test thoroughly before committing to the cutover. Keep Mailchimp paused (not deleted) until you are confident Klaviyo is working correctly. Once you are live on Klaviyo, remove the Mailchimp integration and cancel your Mailchimp account.

Do I need to warm up my domain when switching to Klaviyo?
Yes. Even if you have been sending from the same domain via Mailchimp, Klaviyo uses different sending infrastructure. Start by sending to your most engaged 10–20% of subscribers and gradually expand over two to three weeks. Sudden volume spikes from a new sending infrastructure trigger spam filters regardless of list quality.

What if I am on Shopify — is there anything different?
Yes. Disconnect your Mailchimp-Shopify integration before connecting Klaviyo. Running both integrations simultaneously can trigger double opt-in emails to your subscriber list. Connect Klaviyo to Shopify first, confirm the sync is working, then remove the Mailchimp-Shopify integration.

Can a certified partner manage the Mailchimp to Klaviyo migration for me?
Yes. Rackwave manages end-to-end Mailchimp-to-Klaviyo migrations for eCommerce brands across the USA, UK, Canada, Australia, and Singapore — including contact migration, flow rebuilding, domain authentication, testing, and domain warm-up strategy.