MailerLite → AcelleMail Migration — Visual Walkthrough

Before you start#

You'll need:

• A MailerLite account with subscriber-export permission
• An AcelleMail installation up and running
• ~30 minutes for <100k subscribers

Export from MailerLite#

In MailerLite's left sidebar, click Subscribers → choose the group/list to export → Export in the toolbar.

MailerLite asks for format (CSV) and which fields to include — select all custom fields you've defined. The file prepares in the background; check Subscribers → Imports / Exports for the download link (usually <2 minutes).

Exported CSV includes: email, name, all custom fields, signup date, opt-in source, segments memberships.

Import into AcelleMail (the same 6 clicks for every source)#

Once you have the CSV exported from your previous platform, the import flow in AcelleMail is identical regardless of where the data came from.

1. Open your destination list#

In AcelleMail's sidebar, click Audience → choose the list that will receive the migrated subscribers (or create a new one — New list button top-right).

You'll see a per-list overview card with subscriber counts:

2. Click "Import" in the list toolbar#

The wizard entrypoint is on the list detail page:

3. Upload your CSV#

Drop the CSV file from the previous platform into the upload area:

AcelleMail parses the file and confirms detection:

4. Map the columns#

The wizard auto-detects standard columns (email, first_name, last_name) and shows green Mapped to EMAIL chips. Adjust manually for any non-standard column from the source:

5. Pick duplicate handling#

In the same screen, choose what AcelleMail does when a subscriber already exists in this list:

• Skip — keep the existing row, don't overwrite
• Update — overwrite name/tags/custom fields with values from the CSV
• Unsubscribe — mark existing rows as unsubscribed (rare; used when re-importing an opted-out list)

6. Run the import#

Click Start import. The job runs in the background — close the popup, work elsewhere, return to Audience → [list] → Import to see progress:

You'll see Pending → Running → Complete per import job, with rows-imported / rows-skipped / errors counts.

After the import#

• Verify list count matches your expected size (rows that failed validation appear in the Errors column with a downloadable error CSV).
• Re-tag if needed — for behavioural data that doesn't fit a CSV column (e.g. "opened campaign X"), you may need to re-create the tag via segmentation rules.
• Pause for warm-up — if the imported list is large (>10k) and your sending IP is new or recently rotated, run a short warm-up campaign to your most-engaged 10% before the full send. See IP warm-up best practices for the schedule.

Rebuilding MailerLite automations#

MailerLite's automation workflows map to AcelleMail's Automations. Equivalent triggers:

Merge-tag syntax differences#

# MailerLite v2 API token from Integrations → API
curl -X GET "https://connect.mailerlite.com/api/subscribers?limit=100&page=1" \
  -H "Authorization: Bearer <MAILERLITE_API_TOKEN>" \
  -H "Accept: application/json" \
  -o mailerlite-subscribers.json

ACELLE_TOKEN="..."
ACELLE_LIST_UID="..."

jq -c '.data[] | {email: .email, first_name: .fields.name, last_name: .fields.last_name}' mailerlite-subscribers.json \
  | while read sub; do
      curl -X POST "https://acellemail.com/api/v1/subscribers" \
        -H "Authorization: Bearer $ACELLE_TOKEN" \
        -d "{\"list_uid\":\"$ACELLE_LIST_UID\",\"subscriber\":$sub}"
    done

Related articles#

• Importing contacts CSV — best practices and field mapping
• Migration from Mailchimp to AcelleMail
• Building a welcome email series in AcelleMail
• Email list hygiene