IMAP: one mailbox, more screens.
IMAP lets an email app work with messages and folders on a mail server. It fits a routine that moves between a phone, a laptop, and webmail, provided you understand which changes synchronize and which data remains local.
- Central message store
- Server mailbox
- Useful for
- Several connected devices
- Offline access
- Depends on downloaded content
- Remember
- Synchronization is not backup
Changes can travel in both directions
When your client changes a server folder or a message flag, that state can become visible to other connected clients. This is useful for keeping track of what you have already read. It also means that a mistaken deletion or move can affect the view on another device.
Local folders are different. An app can keep a folder on your computer that does not exist in the IMAP account. Before dragging an important message, check whether the destination is local storage or a server folder.
Give important folders a clear home
Sent, Drafts, Archive, and Trash may be mapped differently by different applications. Send one test message from each device and look at where copies appear. Check whether archiving moves a message, changes a label, or uses a provider-specific convention.
A client may hide unsubscribed folders or download only recent messages. If something looks missing, compare the server view in webmail before changing retention or deleting an account from your app. Folder visibility, a search filter, and actual data loss are different problems.
Separate offline use from recovery
Offline access depends on the app having downloaded the message content you need. A visible subject line does not prove that the full body or attachment is cached. Test a representative message with the connection disabled before travel.
A synchronized cache can follow a server deletion once it reconnects. For recovery from accidental loss, maintain a separate, restorable backup or export with a retention policy you understand. Our IMAP field guide walks through the differences using everyday folder operations.
The IMAP4rev2 protocol specification (RFC 9051)
Questions about imap & sync
Does IMAP also synchronize contacts and calendars?
IMAP concerns email messages, folders, and related state. Contacts and calendars normally need separate provider features or protocols.
Can I keep IMAP messages only on my computer?
A local archive may be possible in your app. Copying and moving have different effects on server storage, so test the workflow and back up the local destination.