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IMAP Transfer
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Back up and
move your mail

Switch providers without losing a single message, or back up your mailbox before you cancel it. Free, for macOS, Windows and Linux.

Download

Version 0.2.2. All systems and checksums

IMAP Transfer with three accounts in the sidebar. The open account offers back up, restore, migrate and optimize; its migration target is the same address on another server.

One file per message

A backup is an ordinary folder: one .eml file per message, sorted like your account. Every mail program opens these files, with or without IMAP Transfer.

  • After the first run, only new mail is fetched.
  • Mail you delete in the account stays in the backup.
  • An mbox export takes everything to Thunderbird or Apple Mail.
anna@example.com/
├── README.txt
├── imaptransfer.db
└── mail/
    ├── INBOX/
    │   ├── 2024-05-03_Invoice May_3f2a9c01b4.eml
    │   └── 2024-05-06_Lunch on Friday_8c41d27e90.eml
    ├── Archive/
    │   └── 2023/
    │       └── 2023-11-20_Contract_b7e0a5f312.eml
    └── Sent/
        └── 2024-05-04_Offer for the garden_51d9c0e6a8.eml
The backup of anna@example.com on disk. The index next to the mail remembers folders, flags and dates.
The plan of a migration from kontakt@example.org on imap.example.net to the same address on mail.example.org: a notice that nothing changes in the source, the Sync option, and five folders with their targets and message counts.

From provider to provider

Choose the target account, and IMAP Transfer shows every folder and where it goes: Sent becomes Sent Items, a missing folder is created. Mail that is already there is skipped.

The old account stays as it is. The migration only reads from it.

Until you have switched over, Sync keeps the new account in step with the old one: what you delete or move there happens here too.

Before you ask

Stop whenever you like

Close the laptop or lose the connection: the next run continues where the last one ended, without a single duplicate.

Duplicates cleaned up

A test run lists every exact copy and changes nothing. Only then do you decide; one of each message stays.

Any IMAP provider

Gmail, Outlook, iCloud, GMX, WEB.DE, T-Online, IONOS, Posteo and every other. The app knows their settings and tells you what to prepare.

Gmail labels kept

A message with five labels is stored once and goes back into all five when you restore it.

On the command line

The same engine runs on servers, NAS boxes and from cron, as imaptransfer. It needs Node.js 22.18 or newer, or Docker.

Exit codes tell a script what happened: 0 done, 2 done but some messages failed, 1 failed, 130 stopped.

# Back up; later runs only fetch what is new
npx imaptransfer backup ~/Backups/anna --user anna@example.com

# Every night at 2:00 (crontab -e)
0 2 * * * imaptransfer backup /srv/backups/anna --user anna@example.com --password-file /root/.anna-imap --quiet

# Move an account and keep it in step
imaptransfer migrate --from-user anna@example.com --to-user anna@example.org --sync

# On a NAS
docker run --rm -v /volume1/backups/anna:/backup -e IMAPTRANSFER_PASSWORD \
  ghcr.io/sebastian-scherhans/imaptransfer backup /backup --user anna@example.com

Download

Version 0.2.2, released on 30 October 2026. Checksums: SHA-256.

IMAP Transfer is free, and liability is limited accordingly. Back up your mail before you restore, migrate, sync or clean up. About liability

macOS

A disk image. Apple silicon for Macs with an M chip, Intel for older Macs.

  • Apple silicon 121 MB

    SHA-256 93d16418404a41d643098a2ad4d7c96d73c457081f62e0ba0a16c5a9b2d7f862

  • Intel 128 MB

    SHA-256 52d10f1c01228dba12b572c65bd17ae4c20897cb31c643d4f7451f9d8573ff91

Windows

An installer. Intel and AMD for most PCs, ARM for laptops with a Snapdragon chip. We have applied to the SignPath Foundation for code signing; until then Windows warns when you start the installer.

  • Intel and AMD 122 MB

    SHA-256 e670e461c676dc9b4cf0a0c94179ad935a5d951bb04c4e5ce7f7d78d3fda81ac

  • ARM 116 MB

    SHA-256 4d7df99d688304701b71b6a2e37b23928ca6f8d63c99c9fb7597b240207a889f

Linux

The AppImage runs almost anywhere, the .deb package on Debian and Ubuntu.

  • AppImage, x64 126 MB

    SHA-256 6f9d6b7026ab79eaca3bf4cd9eda08bf63887edfa8c2326836fec95a0b6cf40e

  • .deb, x64 101 MB

    SHA-256 d86b52c33da0e2d6a203b7b4df1a51182170dc89d7869dae7ea9f6cd29426b49

  • AppImage, ARM64 128 MB

    SHA-256 e1954aa48ab79ea104c3f276c0e044712f500ffa0694186ce7b9924a418c223c

  • .deb, ARM64 96.2 MB

    SHA-256 0fd5978724e1e194d45b8228f824eb82b671a03ba58d3799ed3f2fe7ca3906df

Check the file

Drop the downloaded file here, or choose it. Your browser computes the checksum itself and compares it with the checksums above; the file does not leave your computer.

Or in a terminal:

  • macOSshasum -a 256 ~/Downloads/imaptransfer-0.2.2-mac-arm64.dmg
  • Windows (PowerShell)Get-FileHash $HOME\Downloads\imaptransfer-0.2.2-windows-x64.exe
  • Linuxsha256sum ~/Downloads/imaptransfer-0.2.2-linux-x86_64.AppImage