Switching email platforms sounds simple on paper: export your contacts, import them somewhere new, update your DNS records, and you’re done. In practice, it’s one of the riskier moves in email marketing. Automations usually need to be rebuilt rather than copied over. A new sending domain starts with no reputation, even if your old one had years of good history. And a list that looked clean on your old platform can turn up thousands of invalid addresses the moment someone actually checks. None of this means you shouldn’t migrate — plenty of businesses move platforms every year for better pricing, features, or support. It just means a migration needs a proper checklist, not just an export button.
Check your list health before you move anything
The single biggest risk in any migration is moving a messy list onto new infrastructure. Every list accumulates dead contacts over time — addresses that bounced months ago, role accounts, spam traps, subscribers who haven’t opened anything in years. Your current platform has years of sending data that already accounts for these contacts. A new platform doesn’t have that history, so all of that dead weight counts against you again, starting from your very first send.
Before you export anything, run your list through a verification service and remove what comes back invalid. It’s common for a list that looked fine for years to turn out to have a third or more of its contacts undeliverable once actually checked — one enterprise migration case found that a database of 1.2 million contacts included over a third invalid addresses once verified, and moving that data across unchanged would have hurt the new platform’s reputation from day one. Export your suppression list too — unsubscribes, bounces, and complaints — and load it into the new platform immediately, before your first send, so you don’t accidentally re-email someone who already opted out.
It’s also worth exporting engagement history alongside the contact data itself, not just names and email addresses. Which contacts opened or clicked in the last 90 days, which haven’t engaged in over a year, which came from a paid ad versus an organic signup — this context is what lets you warm up gradually and segment sensibly on the new platform, instead of treating every contact as equally “fresh” the moment they land there.
Check your consent records and compliance history
Alongside the list itself, export the proof behind it — when and how each contact opted in, which form or source they came from, and any consent timestamps your current platform stores. This matters for two reasons. First, several data protection rules require you to be able to show how and when someone agreed to hear from you, and that proof is often tied to the platform where the signup happened rather than stored anywhere else. Second, a new platform has no record of your compliance history. If a regulator or an unhappy subscriber ever asks how a specific contact ended up on your list, you want a clear answer on hand — not just “it was already on the list when we migrated.” Keep this data archived somewhere outside either platform, not just inside the one you’re about to leave.
Check whether your automations will actually rebuild
Automations rarely transfer one-to-one between platforms. The logic might be similar — a welcome series, a cart abandonment flow, a re-engagement sequence — but the way each platform builds conditions, delays, and branches is different enough that a straight copy usually isn’t possible. Plan to rebuild each automation from scratch on the new platform, and test every branch of it — every condition, every delay, every possible path a contact could take — before you turn it on for real contacts. It’s worth resisting the urge to redesign your workflows at the same time you migrate them; changing the logic and changing the platform at once makes it much harder to tell which change caused a problem if something breaks.
The same applies to signup forms and landing pages that feed your list. Submit a real test entry through every form connected to your list before going live, so you can confirm new signups actually land where they’re supposed to and trigger the right welcome sequence.
Check your integrations
If your email platform connects to a CRM, an online store, a helpdesk, or any other tool, treat each of those connections as a separate thing to verify — not something that just carries over with the rest of your data. Reconnect each integration individually, and confirm data is actually flowing both ways where it’s supposed to: a test order should show up as a tagged contact, a new CRM lead should land on the right list, a closed support ticket should update the right field. It’s also the moment to check whether the new platform’s version of an integration does everything the old one did — some connections sync more fields, or sync in both directions, while others only cover the basics.
Check your authentication and plan a real warm-up
This is the step most migrations get wrong, because it’s easy to assume a domain with years of good sending history keeps that same reputation on a new platform. It doesn’t. Inbox providers base their trust on both your domain and the actual servers sending the mail. When you switch platforms, you’re sending from different servers they have no data on — so Gmail, Yahoo, and Outlook treat you as a new sender, regardless of how long you’ve been sending elsewhere.
Two things need to happen before you send at volume. First, your SPF, DKIM, and DMARC records need to be set up and verified for the new platform specifically — these don’t carry over automatically, and a mismatch can get your mail rejected outright rather than just filtered. DNS changes can take anywhere from a few hours up to about 48 hours to fully propagate, so this isn’t something to finalize the same day you plan to send. Second, if you’re sending on a new IP, it needs a gradual warm-up — starting with your most engaged subscribers, the ones who opened or clicked in the last 30 to 90 days, and increasing your send volume gradually rather than blasting your full list on day one.
The risk of skipping this is well documented: new IPs that skip warm-up can see spam-folder placement rates over 50% at major mailbox providers in just the first week of sending. A properly warmed-up domain, by contrast, typically reaches stable inbox placement above 95% across major providers within two to four weeks of gradual, consistent sending. That’s the practical reason to follow a warm-up schedule rather than sending your full list on day one — skipping it is a common way for a first campaign on a new platform to land in spam instead of the inbox.
Check your timeline, and don’t cut the cord too early
A realistic migration usually takes a couple of weeks from planning to full cutover, longer for a large list with many automations and integrations. During that window, keep your old platform active rather than shutting it off the moment the new one is live. Run both in parallel for a short overlap: send from the new platform, but leave the old one reachable in case a last-minute signup lands there, or something on the new side needs a quick comparison.
It also helps to migrate in phases rather than all at once. Start with your lowest-risk mail — transactional messages like order confirmations and password resets tend to have the highest engagement and the lowest complaint rates, which makes them a good first test of the new platform’s sending and your integration setup. From there, move to automated flows like welcome series and abandoned cart messages, which reach recently active subscribers who already expect to hear from you. Save your full newsletter list and broadest promotional sends for last, once inbox placement has stabilized and you’ve confirmed the earlier phases behaved as expected.
Only fully cancel the old platform once you’ve confirmed contacts, automations, integrations, and deliverability are all stable — and once you’ve kept a backup of your templates, automation logic, and suppression lists somewhere safe, since you generally can’t retrieve anything from the old platform once your account is closed.
If you’re moving away from Mailchimp specifically
Mailchimp is one of the most common starting points for a migration, and a few of the checks above are worth double-checking if it’s the platform you’re leaving. Mailchimp’s tags and its group-based segmentation don’t always map cleanly onto the list or tag structure other platforms use, so it’s worth confirming how your segments will actually translate before you rely on them for a launch-day send. Its automations — particularly anything built with multi-step Customer Journeys — also need to be rebuilt rather than exported, since the underlying logic doesn’t transfer as a file you can just re-upload elsewhere. If you are thinking about moving from Mailchimp to some more cost-savvy option, read this guide.
The bottom line
Migrations go smoothly when they’re planned like a project, not treated as a simple data export. That means cleaning the list before it moves, rebuilding and testing automations instead of copying them, reconnecting integrations one at a time, and following a real warm-up plan instead of assuming your sending history carries over automatically. None of this makes switching platforms a bad idea — it just takes planning up front instead of fixing problems after they show up.
