What should a successful switch actually change?

Choose one operational problem to solve before comparing platforms. Perhaps your team struggles to update signup forms or assemble the weekly newsletter. Write a specific acceptance test: “Our marketing assistant can prepare and check the newsletter without outside help.”

An ESP is an email service provider: the platform you use to manage subscribers and send campaigns. Mailchimp and Klaviyo are examples. Klaviyo describes migration from another ESP as a replacement process involving contacts, forms and messaging workflows.

Ask for a working demonstration

Whether you are considering Mailchimp or a Mailchimp alternative, ask someone on your team to build a real draft. Test the tasks they will repeat, including selecting recipients and handling an unsubscribe. Use your own acceptance criteria to judge the experience.

Make a budget with separate lines for the subscription, migration work and staff training. Request current terms directly from the provider. Avoid approving the switch before someone owns the transfer and someone owns the final checks.

How do you migrate an email list without losing its meaning?

Export subscription status alongside email addresses. Mailchimp specifically advises keeping subscribed, unsubscribed and cleaned contacts in separate categories during a move. Its migration guidance makes that separation part of preparing your import.

Keep an untouched copy of the original export. Work on a duplicate when renaming columns or checking records. Note which account produced each file so the team can trace a questionable record later.

Reconcile categories, then inspect records

Write down the number of contacts in each status before and after import. Investigate rejected rows and duplicates. Make every unexplained difference a follow-up task rather than accepting a reassuring total.

Hypothetical example: a small online shop has newsletter subscribers and customers who only placed an order. Keep those groups distinct while checking their existing permission records. Do not mark every customer as subscribed simply to make the import easier.

Leave addresses with unclear permission outside your campaign audience while you investigate. For future acquisition, use a separate email list growth plan. Treat rebuilding missing consent evidence as its own task.

How should suppression list migration work?

A suppression list records addresses that should not receive your email communications. Klaviyo says that, when you are not using its built-in migration integration, you must upload existing bounces and unsubscribes directly to its suppression list. Follow its suppression instructions for that migration route.

Before importing subscribers, keep campaigns and automated messages inactive. Apply sending restrictions through the destination’s designated controls. Then check that importing contacts has not changed those restrictions.

• Export excluded addresses separately.
• Keep the reason for exclusion where available.
• Check how the destination applies account-wide restrictions.
• Use an address you control to test exclusion.
• Transfer new unsubscribe requests during the overlap period.

Test behavior, not just a label

Set a clear acceptance condition: your suppressed test address must not qualify for a marketing send. Ask the provider for help if you cannot verify that condition. A profile displaying an imported label is not sufficient evidence for your checklist.

Klaviyo distinguishes its built-in integrations from manual migration. That distinction is provider-specific, so verify the exact route you are using. Do not assume another integration transfers the same records.

What SPF, DKIM and DMARC setup does Gmail require?

Check authentication, meaning verification of the sender, before sending from the new service. Google requires SPF or DKIM for all senders to personal Gmail accounts, and SPF, DKIM and DMARC for bulk senders. It recommends all three generally. Google’s sender requirements distinguish the minimum from that recommendation.

• SPF identifies services authorized to send for your domain.
• DKIM provides a digital signature used to verify the sending domain.
• DMARC sets handling instructions for authentication failures and checks domain alignment.

These definitions follow Google’s authentication guidance. Domain alignment means the visible sender domain must match the relevant authenticated domain under DMARC’s rules. Give the setup task to whoever manages your domain settings.

Count the domain’s Gmail traffic

Google defines a bulk sender as sending close to 5,000 or more messages to personal Gmail accounts within 24 hours. Traffic from the same primary domain counts together, including subdomains. Once assigned, bulk sender status is permanent. Google’s FAQ explains the calculation.

Review traffic across your services before deciding which requirements apply. A platform switch does not remove that permanent classification. Ask your provider to check a real test message, including its visible sender and authentication results.

Bulk marketing and subscription messages must support one-click unsubscribe and contain a clearly visible unsubscribe link. Google requires both. Include both checks in your launch checklist.

Which subscriber journeys should you test?

Test every route into your list. Klaviyo’s checklist includes embedded website forms, third-party forms and checkout subscriptions, plus automated replies and saved templates. Its migration instructions provide a useful inventory.

Start where the customer starts

Submit each form yourself using a controlled test address. Check the resulting profile, its permission status and the message it receives. Then unsubscribe and inspect the status again.

If you offer a download, include the delivery email and download link in this test. Use the lead magnet planning guide when reviewing that promise. Keep the migration test focused on whether the promised resource arrives correctly.

For a cafe, a hypothetical test could start with the signup link printed beside the till. Review those entry points alongside your QR code marketing plan. Also inspect invitations used in your referral programme so they lead to the intended form.

Keep a written handover for each automated message: when the old version stops, when the replacement starts and who checks it. If you also run text campaigns, keep their permission checks separate in your SMS marketing plan. Do not infer one channel’s permission from another during import.

When should you send and close the old account?

Send only after the contact, exclusion and journey checks pass. My recommendation is to begin with a small group of recently engaged, clearly subscribed readers. Choose the size with your provider instead of copying an arbitrary daily growth schedule.

Email deliverability concerns whether messages reach recipients successfully. Google warns that messages failing its requirements may be rejected or marked as spam. Use its guidelines when investigating delivery problems after the switch.

Use a short launch log

• Record the audience selected and the campaign sent.
• Review delivery failures and their stated reasons.
• Check complaints and unsubscribe requests.
• Confirm customer replies reach a monitored inbox.
• Pause expansion if a required check fails.

Before closing the old account, save the records your team needs and confirm who owns ongoing monitoring. Klaviyo recommends watching the former lists for a few days after replacing forms. New subscribers there may indicate a form still points to the old system. Its final migration checks explain this step.