How to Migrate to Klaviyo Without Hurting Email Deliverability

Recently, we have had several clients come to us running their email programs on platforms that were holding them back. In most cases, the symptoms looked the same. Limited segmentation. Clunky automation. Reporting that did not tell the full story. And email performance that had clearly plateaued.

For designer brands, our recommendation is almost always Klaviyo. It is built specifically for ecommerce, integrates deeply with your tech stack, and gives you far more control over personalization, automation, and data. Because of that, we have completed several migrations to Klaviyo recently from a range of other platforms.

Email platform migration is not for the faint of heart. When done incorrectly, it can seriously impact deliverability, engagement, and revenue. That is why we are breaking down exactly what you need to know before making the move, and how to do it the right way.

Why Migrate to Klaviyo

The biggest reason brands migrate to Klaviyo is simple. You’ve outgrown your current platform.

As ecommerce businesses scale, email needs to do more than send newsletters and deliver basic automations. You need advanced segmentation based on real customer behavior. You need flows that adapt to where someone is in their lifecycle. And you need reporting that clearly ties email activity back to revenue.

Klaviyo excels here.

It connects directly to ecommerce platforms like Shopify (our preferred ecomm platform), WooCommerce, and BigCommerce. That means you can segment and trigger emails based on purchases, browsing behavior, average order value, product categories, and more. You are no longer guessing who your audience is. You are responding to what they actually do.

Another major driver is automation. Klaviyo allows brands to build sophisticated flows that go far beyond a welcome series. Think post-purchase education, replenishment reminders, winback campaigns, VIP nurturing, and cross-sell flows that feel timely and relevant. It’s not that you can’t do these on other ESPs, but Klaviyo offers more and better options for the scaling ecommerce brand. 

Finally, Klaviyo’s analytics are a game changer. You can see exactly how email contributes to revenue, not just opens and clicks. For leadership teams and founders, that visibility matters.

Migration Plan for Success

• Take stock of what you have today
  Know what lists, automations, opt-ins and campaigns are currently running so nothing important gets lost in the move.

• Clean up your list before migrating
  Removing inactive subscribers now helps protect performance later. A smaller, engaged list always wins.

• Focus on the essentials first
  Start with the emails that matter most to revenue, like welcome emails, abandoned cart, and post-purchase follow-ups.

• Set up the basics correctly
  Make sure your sending domain and integrations are properly configured before you start sending.

• Choose the right time to move
  Avoid migrating during sales peaks or major launches. Give yourself breathing room to monitor results.

If you have outgrown your current ESP and you’re ready to make the switch to Klaviyo, we always recommend consulting with an expert who can help guide your migration. This is because you want to make the shift with as little impact to your deliverability as possible. It’s critical that you follow a domain warming process – a process of gradually increasing the amount of contacts you are emailing little by little. 

List Warming Process 

• Start with your best subscribers
  Begin by emailing people who have recently opened or clicked. They are the most likely to engage and least likely to cause deliverability issues.

• Increase sending gradually
  Do not email your full list right away. Slowly scale up over a few days or weeks (depending on how often you send) to build trust with inbox providers.

• Watch performance closely
  Pay attention to open rates, clicks, and complaints. These signals tell you if things are going well.

• Lead with value early on
  Educational and brand-focused emails perform better than heavy promotions during the warm-up period.

• Be patient with the rest of your list
  Older or less engaged subscribers can wait. Rushing to email them can hurt your results.

Best Practices for Email Migration

• Set up proper authentication
  Ensure SPF, DKIM, and sending domains are configured correctly before you send your first campaign. This step is critical for deliverability.

• Test everything before going live
  Preview emails across devices, click every link, and place test orders to confirm ecommerce events and triggers are firing correctly.

• Maintain consistent sending behavior
  Avoid sudden spikes in volume or frequency. Gradual increases help protect your sender reputation and keep inbox providers happy.

• Keep branding and voice consistent
  Your emails should feel familiar to subscribers, even though they are coming from a new platform. Consistency builds trust and recognition.

• Do not rebuild everything at once
  Focus on getting core flows and campaigns live first. Once the foundation is solid, you can layer in more advanced strategies.

Migrating to Klaviyo can be one of the best decisions an ecommerce brand makes for its email program. The upside is significant, but only if the migration is handled thoughtfully.

Deliverability implications are real, and mistakes can be costly. With the right plan, a clean list, and a disciplined warm-up process, you can protect your reputation and unlock far more value from email.

If you are considering a move to Klaviyo and want to make sure it is done right, this is not a step to rush or take lightly. When in doubt, get expert support and treat migration as the strategic investment it is.

Email marketing is too important to get wrong.