The one-way door nobody advertises
Every email tool has a beautiful import flow, because imports are how they win customers. Exports are how they lose them, so exports get exactly as much love as the law requires. The pattern repeats across the whole industry: the export button exists, it produces a real CSV, and the CSV is quietly missing the parts that made your data valuable.
Two examples we know well, because we built the fix for both:
ActiveCampaign: the export that forgets your notes
ActiveCampaign's contact export gives you contacts and standard fields. Notes, the free-text history your team attached to subscribers over the years (why they churned, what they asked for, which plan they were quoted), are simply not in the file. They exist in the API. They show on every contact page. The export skips them. Migrate on the native export and your new platform receives contacts with amnesia: correct emails, no memory.
Our ActiveCampaign notes exporter pulls contacts with custom fields and every note, in one clean CSV, using your own API key in memory only. If you are leaving ActiveCampaign, run it before you cancel. Most platforms cut API access the moment the subscription ends, and then the notes are gone for good.
MailPoet: your list is inside WordPress, sort of
MailPoet lives inside WordPress, which sounds like you own everything. In practice, getting subscribers out with all their custom fields means fighting the plugin's export screen, which handles simple cases and struggles with multiple lists and custom field sets. Our MailPoet exporter talks to a tiny read-only connector plugin and pulls any list with every custom field intact, ready for whatever platform comes next.
The migration checklist that saves regret
- Export while you still have access. API keys usually die with the subscription. Export first, cancel second. Never the other way.
- Take the fields, not just the emails. Custom fields are your segmentation. An email-only export means rebuilding every segment by hand on the new platform.
- Take the history. Notes and context are the difference between a list and a relationship. If your exporter drops them, use one that does not.
- Export suppression lists too. Unsubscribes and bounces must travel with you. Mailing someone who unsubscribed on the old platform is a spam complaint, and possibly a legal problem, on the new one.
- Keep a dated archive copy. Even after the import works, keep the raw export. Six months later, someone will ask what a field meant.
You only find out what your email platform withholds on the day you leave. Rehearse the exit before you need it.
Rebuilding segments without rebuilding your life
Here is where taking custom fields pays off. Segments on any platform are just saved filters over fields. "Plan = pro AND city = Mumbai" is a segment on ActiveCampaign, Mailchimp, or anything else, as long as the fields made the trip. Migrate with fields intact and rebuilding your segments is an afternoon of clicking filters that already work. Migrate emails-only and every segment becomes a research project: who was in it, why, and can we even know anymore?
The 30-day parallel run
Do not flip a switch. Run both platforms for a month. Keep the old one alive (downgrade it if you can) for 30 days after the new one goes live. Send from the new one. Keep the old one for reference and for the stragglers: the forms and automations you forgot were pointed at it. Almost every migration finds one embedded signup form on a landing page nobody remembered. The parallel month turns that discovery from an incident into a chore. Cancel at day 30, after one last export of anything that trickled in.
Warm the new house before moving in
One cost of switching that surprises people: your sending reputation does not migrate. The new platform sends from new infrastructure, and mailbox providers distrust sudden volume from an unfamiliar source. Blasting your full list on day one from a cold setup is how migrations become deliverability incidents. Ramp up over two to three weeks, starting with your most engaged readers. And finish the authentication homework, SPF, DKIM and DMARC on your domain, before the first real send, not after the first bounce report.
Frequently asked questions
Does ActiveCampaign's export include contact notes?
No. The native contact export covers contacts and fields but omits notes entirely. Notes are available through the API, so an API-based exporter can produce a CSV of contacts with custom fields and every note included.
How do I export MailPoet subscribers with custom fields?
MailPoet's built-in export handles simple lists but gets awkward with multiple lists and custom field sets. A read-only connector that queries MailPoet's data inside WordPress can export any list with all custom fields preserved.
What should I export before cancelling an email platform?
Contacts with all custom fields, notes and interaction history, your unsubscribe and bounce suppression lists, and ideally campaign performance data. Do it while your subscription and API access are still active.
Why do suppression lists matter in a migration?
Unsubscribes must be honored across platforms. If suppressed addresses do not travel with you, the new platform may mail people who opted out, which damages deliverability and can violate anti-spam law.