Back up your mailbox to a .zip archive
Free up to 5GB. Read-only: your mailbox is never changed.
How it works
- Enter the credentials for the mailbox to back up — address, password (or app password) and the IMAP server settings.
- Start the backup — MailSync connects read-only and starts going through all your folders.
- MailSync downloads all your messages — folders, subfolders and attachments, one .eml file per message.
- A .zip archive is generated — it reproduces the exact folder structure of your mailbox.
- Download your archive — a completion email is sent if you provide one; the archive stays available for 48 hours.
Read-only: your mailbox is never modified at any point. MailSync only reads messages to build the archive; nothing is deleted, moved, or marked as read on the server.
Use cases
- Archiving before closing an address — you're closing a mailbox (end of subscription, changing host) and want to keep a full copy before it becomes unreachable.
- Legal or business record-keeping — you're required to keep business or administrative correspondence for a given period, regardless of your email provider.
- A safety net before a big clean-up — you're about to delete a large number of messages or reorganize your folders, and would rather have a backup in place first.
- Keeping a record before leaving an employer — before your work mailbox is closed, you keep an archive of your correspondence for yourself or to hand over to your successor.
What this tool doesn't do
- The backup only works over IMAP: mailboxes only reachable via POP3, or through a closed proprietary Exchange connector, can't be backed up with this tool.
- The archive contains your messages (.eml), their attachments and the folder structure; it does not contain your contacts, your calendar, or any server-side filtering rules.
- The archive stays downloadable for 48 hours after the backup finishes, then it's permanently deleted from our servers.
- Beyond 5GB, finishing the operation requires a one-off payment or the Premium plan, which removes the volume cap.
Frequently asked questions
What format are my emails backed up in? +
You get a .zip archive containing one .eml file per message, organized in the same folder structure as your mailbox. The .eml format is an open standard, readable by Thunderbird, Outlook, Apple Mail and most email clients.
What exactly does the archive contain? +
The archive contains all your messages (one .eml file each, attachments included) organized in the same folder structure as your original mailbox. It does not contain your contacts, your calendar, or any server-side filtering rules: only the messages and their folder organization are backed up.
How long does the archive stay available? +
The archive is downloadable for 48 hours after the backup finishes, then it's permanently deleted from our servers. Make sure to download it within that window; after that, you'll need to run a new backup.
Does the backup change my mailbox? +
No. The connection is read-only: no message is deleted, moved, or even marked as read. Your mailbox stays exactly as you left it.
Can I re-import the archive later? +
Yes. You can re-import this .eml archive into any IMAP mailbox using MailSync's import tool, or into any email client that supports the .eml format (Thunderbird, Outlook, Apple Mail).
Are my credentials kept after the backup? +
No. Your IMAP credentials are encrypted for the whole duration of the operation, then erased as soon as it finishes. If you're signed in to your MailSync account and chose to save the mailbox, only that one is kept (encrypted) so you don't have to retype credentials next time; you can delete it at any time.
What mailbox size is supported? +
The backup is free up to 5GB. Beyond that, the first 5GB are backed up for free, then you finish the operation with a one-off payment or by switching to Premium, which removes this limit.
Which providers are supported? +
Any provider offering standard IMAP access: Gmail, Outlook/Microsoft 365, Yahoo, iCloud, OVH, o2switch, and the vast majority of professional hosts. You simply need the credentials and the IMAP server settings (address, port, SSL).