Moving to a new email platform is mostly careful bookkeeping. Done well, your subscribers won’t notice anything except better emails. Done in a hurry, you can end up emailing people who unsubscribed, losing months of engagement history and landing in spam. Here’s how to move safely.
Plan the move
Give yourself two to six weeks, depending on the size of your list and how many automations you run. Avoid switching right before a big moment, such as Diwali, a product launch or year-end, when you can’t afford a dip.
Agree who owns the migration and who signs off each step. One person keeping the checklist avoids the classic gap where everyone assumes someone else moved the suppression list.
- Make an inventory: lists, segments, tags, custom fields, forms, templates, automations and integrations.
- Decide what to leave behind. Migration is a good time to retire old templates and long-inactive contacts.
- Check your current contract’s notice period and renewal date.
Export everything you need
- All contacts with their custom fields and tags, both subscribed and unsubscribed
- Consent data: when and how each person signed up, and any double opt-in confirmations
- Suppression lists: unsubscribes, hard bounces, spam complaints and manual blocks
- Engagement data such as last open and last click dates, where your old platform allows it
- Templates as HTML, plus any images hosted on the old platform
- Screenshots or notes of each automation’s logic, timings and conditions
- Form embed codes, and a note of every page they appear on
Some platforms delete hosted images when you close your account. Download them before you cancel, so older emails don’t show broken images.
Set up and rebuild
- Import contacts and suppressions together Bring in your suppression list first or alongside your contacts, so nobody who opted out is re-subscribed by accident. Map fields carefully and keep the original sign-up dates.
- Rebuild templates Import your HTML designs or rebuild them in the new builder. Replace the old platform’s merge tags with the new syntax.
- Recreate automations Rebuild each journey from your notes. Decide whether people who were midway should restart, skip ahead or stay out.
- Replace forms and integrations Swap form embeds, reconnect your store or CRM, and point any webhooks or API calls at the new platform.
MailNesto imports Excel, CSV or pasted lists including consent and tag columns, imports designs from HTML or ZIP files, and applies your suppression list to every import.
Authenticate and warm up
Your new platform sends from different servers, so update DNS before your first campaign: add the new DKIM records, include the new sender in your SPF record, and keep your DMARC record in place. Leave the old platform’s records until you have completely stopped sending from it.
Your domain has history, but the new sending IPs may not. Start with your most engaged contacts and build volume over two to four weeks, rather than mailing your whole list on day one.
Run in parallel, then cut over
- Send test campaigns Send to your team and to a seed list on different mailbox providers. Check rendering, links, merge tags and the unsubscribe flow.
- Overlap for a while Move new sign-ups and your most engaged segment first, while the old platform handles the rest. Sync unsubscribes between the two every day.
- Cut over Once volume and reputation are stable, send everything from the new platform. Switch off old automations at the same time so nobody gets two welcome emails.
- Close the old account Do a final export of unsubscribes and bounces collected during the overlap, import them, and then cancel.
Common pitfalls
- Re-importing unsubscribes. This is the most serious mistake: it breaks consent rules in many countries and generates complaints. Always bring suppressions across.
- Merge-tag differences. *|FNAME|*, {{first_name}} and %FIRSTNAME% are not interchangeable. Search every template and automation for the old syntax.
- Losing engagement history. Without last-open or last-click data you can’t pick an engaged segment for warm-up. Export it, or at least keep a list of recent engagers.
- Duplicate sends during the overlap. Turn off each old automation as you turn on its replacement.
- Forgotten forms. One old embed on a rarely visited page can keep feeding the old platform for months.
- Changing too much at once. A new platform, new sender name and new design together make it hard to tell what caused a dip.
After the move
- Compare your first few campaigns with your historical averages for opens, clicks, bounces and complaints.
- Watch Google Postmaster Tools for your domain’s spam rate and authentication results during the first month.
- Confirm that every form, integration and automation now feeds the new platform.
- Update your internal notes and give each teammate a login with the right role.
- Store your final exports from the old platform safely, in line with your retention policy.
Questions
What about my old campaign reports?
Reports usually can’t be imported into a new platform. Export the summary figures you care about, such as opens, clicks and revenue per campaign, as a spreadsheet so you keep a baseline to compare against.
Will my open rates drop after switching?
A small, temporary dip is common while the new sending setup builds reputation. Warming up with engaged contacts keeps it short.
Do I need to ask subscribers to opt in again?
Not if you have valid consent and bring the records with you. Re-permission campaigns tend to lose a large share of a list unnecessarily. Only re-confirm contacts whose consent you can’t show evidence for.
Can I keep my sender address?
Yes. Your From address and domain stay the same. Only the sending service changes, which is why you update your DNS records.