shipmail

Mailbox import

Bring your old email along when you move to Shipmail. The import copies your messages in the background while you keep working, preserves your folder structure, read state, and original dates, and skips duplicates so running it again is always safe.

Last updated

Supported sources

  • Gmail, Yahoo, AOL, iCloud, Fastmail, Zoho, and any IMAP provider: connect with an app password. The wizard walks you through creating one for each provider.
  • Outlook.com and Microsoft 365: click Sign in with Microsoft. Microsoft no longer supports app passwords for mail, so this is the only way to connect, and it also imports your Outlook contacts.
  • File uploads: Google Takeout archives (.mbox, including split and gzipped exports), Proton Mail Export Tool output, Tuta exports, and generic MBOX or EML zip files from Thunderbird or Apple Mail. Files can be up to 4 GB each.
  • Contacts: upload a .vcf (vCard) file from any provider during the import, or let the Microsoft sign-in bring Outlook contacts automatically.

Starting an import

  1. Go to the Mailboxes page and choose Import mail on the mailbox you want to fill. New mailboxes also offer the import right after creation.
  2. Pick your old provider and connect. The wizard checks the connection and shows your folders with message counts before anything starts.
  3. Choose what to import: folders, a time range (everything, or the last 12, 3, or 1 months), and whether spam and trash come along. They are skipped by default.
  4. Review the storage check. While you pick folders, shipmail measures the real size of your source mailbox and tells you plainly whether the import fits your plan, may nearly fill your mailbox, or needs more storage. Large mailboxes also get an honest time estimate.
  5. Start the import and close the page. Mail shows up in your inbox as it imports. The progress card shows how much is done and, once it has enough throughput to be reliable, a live estimate of the time left. You get an email with a per-folder report when everything is done.

The storage check

  • For IMAP sources, shipmail measures message sizes directly from the provider without downloading anything, so the number you see is real, not a guess. Very large mailboxes are sampled to keep the check quick.
  • For file uploads, the staged file sizes are used. Compressed archives are shown as an estimate since they expand during import.
  • An import only gets blocked when the measured size clearly does not fit the free space in the mailbox. Estimates never block. If an import would not fit, you can upgrade your plan, uncheck folders, or narrow the time range.
  • If storage fills up mid-import anyway, the import pauses cleanly and resumes after you free space or upgrade. Nothing is lost.

Gmail specifics

Gmail labels become Shipmail folders. A message with several labels shows up in each of those folders but is stored only once, with no duplicates. Gmail's Starred and Important views are skipped, because they only mirror mail that already comes across in your other folders. Google limits IMAP downloads to about 2.5 GB per day, so a large mailbox imports over several days. Shipmail paces the transfer automatically, pauses when Google's daily limit is reached, and resumes on its own. The progress card always shows what is happening and why.

Safety and credentials

  • Your old account's password is encrypted, used only for this import, and deleted the moment the import finishes, fails, or is cancelled.
  • Imports are deduplicated by message identity. Running an import again only picks up new mail, which is the recommended way to catch stragglers before you close the old account.
  • Cancelling keeps everything imported so far. Messages larger than 50 MB are skipped and counted in the report.

Importing via the API

Everything above is also available programmatically: create imports, poll progress, and stage file uploads through the REST API, the TypeScript SDK, or the Shipmail MCP server. See the mailboxes API reference for the endpoints.