Mail-Backup stores your emails locally as eml files (as delivered by the server). Eml-Files can be viewed at least with Thunderbird, even extracting attachments.

• Download emails via IMAP as eml files.
• Configure local storage paths and file names based on email attributes (like date).
• Handles duplicated backups.
• Limit/filter by "newer than x days" number.
• Limit/filter by "older than x days" number.
• Delete files from server after backup

Tipp: You may search your emails with a desktop search app, like Recoll.

• Tested only on Linux and macOS. There is no plan to support Windows, even though there should be only minor issues with path handling.
• Some (minimal) experience with the UNIX command line and YAML files required!

Prerequisites:

sudo apt-get install python3-dev python3-pip python3-venv python3-wheel -y

git clone https://github.com/rosenloecher-it/mail-backup

cd mail-backup
python3 -m venv venv

# activate venv
source ./venv/bin/activate

# install required packages
pip install --upgrade -r requirements.txt
# or: pip install --upgrade -r requirements-dev.txt

Prepare your own config file based on ./mail-backup.yaml.sample.

# cd ... goto project dir
cp ./mail-backup.yaml.sample ./mail-backup.yaml

Edit your mail-backup.yaml. See comments there. Make sure your IMAP credentials are configured. The password may be set alternatively via command line.

You may configure the storage path per email attributes. Available replacement tokens:

• Email time settings (not the download time): YEAR, MONTH, DAY, HOUR, MINUTE
• Common email settings: UID (IDs are only unique per folder), SUBJECT, TO1 (first receiver email), FROM (email, no name)

Example:

../{FOLDER}/{YEAR}{MONTH}{DAY}-{HOUR}{MINUTE}-{FROM}-{SUBJECT}-{UID}.eml

Gets to:

./[email protected]/INBOX/20210401-1604-no-reply.company.com-The.subject-123.eml

Not existing paths get created automatically.

All attribute strings get preprocessed in a quite opinionated manner, e.g. UTF-8 characters and white space gets removed. "Fwd:", "Re:" in subjects are removed too.

The handling of already existing mails files can be configured. Just set when_exists (see mail-backup.yaml.sample). Available options:

• skip: Skip the email backup if a file with the proposed name already exists.
• overwrite: Overwrite the email backup if a file with the proposed name already exists.
• compare: Even by using the UID, there is no guarantee that different emails get different file names, so emails could get overwritten. In compare mode existing files gets compared with downloaded email content and written with a postfixed path ("mail.eml" => "mail.2.eml").

With last_days you can limit the backup to the most recent emails (see mail-backup.yaml.sample).

With limit_days you can limit the backup to only backup emails older than specified days (see mail-backup.yaml.sample).

With delete you can define to delete the mails from the server. You will be promped on execution to confirm this!

# see command line options
./mail-backup.sh --help

./mail-backup.sh -c ./mail-backup.yaml

MIT © Raul Rosenlöcher

The code is available at GitHub.