The main limitations of MailerLite subscriber imports
A syntactically valid email address may still be inappropriate to market to. Record how and when the person subscribed, what they were told, and which messages the permission covers. Do not import purchased, scraped, or unrelated lists. Preserve unsubscribed, bounced, complaint, and suppression records so they are not accidentally reactivated.
Review applicable law and platform policies for the audience and geography. This guide is operational context, not legal advice. When permission evidence is incomplete, isolate or exclude the records instead of treating a successful CSV upload as permission to send; import capability and lawful, expected contact are separate tests.
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Start a 14-day MailerLite trial →Prepare the file
Use one row per person, clear column names, UTF-8 encoding, and only required fields. Remove leading or trailing spaces and obvious duplicates without discarding consent evidence. Keep an original export, a cleaned file, and a transformation log.
Map fields explicitly. Avoid turning historical tags into active marketing groups without understanding what each tag meant in the old system.
Choose automation behavior deliberately
During import, confirm target groups and whether group-based automations should start. A bulk migration can unintentionally send an old welcome series, lead magnet, or promotion to the entire audience. Pause or isolate workflows until the staged test proves expected behavior.
Use a small segment first and inspect accepted, rejected, duplicate, unsubscribed, and bounced outcomes. Do not manually force questionable records through merely to match an old count.
Reconcile and retain evidence
Compare totals by status, source, field completeness, group, and suppression. Investigate differences and keep the import report with the mapping and timestamp. Test unsubscribe and preference behavior after migration.
Retain only the evidence and data needed for legitimate operations, secure the files, and delete temporary copies according to a documented retention process. Imports during the 14-day trial are capped at 250 subscribers, the same limit as the Free plan.
The trial import limit here comes from MailerLite's own pages; every source is listed below with the date it was read.
Sources used for this page
These records support the facts and comparisons above. Merchant-controlled records are labeled so you can separate product claims from independent evidence.
- MailerLite subscriber import guidance — Merchant documentation · mailerlite.com · Merchant-controlled · read August 23, 2026
- MailerLite migration resources — Merchant documentation · mailerlite.com · Merchant-controlled · read August 23, 2026
- FTC CAN-SPAM compliance guide for business — Regulatory guidance · ftc.gov · Publisher independence not verified · read August 23, 2026
- MailerLite plans and pricing — Merchant documentation · mailerlite.com · Merchant-controlled · read October 6, 2026
- MailerLite product overview — Merchant documentation · mailerlite.com · Merchant-controlled · read October 6, 2026