Essentials

IMAPClient is an easy-to-use, Pythonic and complete IMAP client library.

Features

• Arguments and return values are natural Python types.

• IMAP server responses are fully parsed and readily usable.

• IMAP unique message IDs (UIDs) are handled transparently. There is no need to call different methods to use UIDs.

• Escaping for internationalised mailbox names is transparently handled. Unicode mailbox names may be passed as input wherever a folder name is accepted.

• Time zones are transparently handled including when the server and client are in different zones.

• Convenience methods are provided for commonly used functionality.

• Exceptions are raised when errors occur.

Example

from imapclient import IMAPClient

# context manager ensures the session is cleaned up
with IMAPClient(host="imap.host.org") as client:
    client.login('someone', 'secret')
    client.select_folder('INBOX')

    # search criteria are passed in a straightforward way
    # (nesting is supported)
    messages = client.search(['NOT', 'DELETED'])

    # fetch selectors are passed as a simple list of strings.
    response = client.fetch(messages, ['FLAGS', 'RFC822.SIZE'])

    # `response` is keyed by message id and contains parsed,
    # converted response items.
    for message_id, data in response.items():
        print('{id}: {size} bytes, flags={flags}'.format(
            id=message_id,
            size=data[b'RFC822.SIZE'],
            flags=data[b'FLAGS']))

Why IMAPClient?

You may ask: “why create another IMAP client library for Python? Doesn’t the Python standard library already have imaplib?”.

The problem with imaplib is that it’s very low-level. It expects string values where lists or tuples would be more appropriate and returns server responses almost unparsed. As IMAP server responses can be quite complex this means everyone using imaplib ends up writing their own fragile parsing routines.

Also, imaplib doesn’t make good use of exceptions. This means you need to check the return value of each call to imaplib to see if what you just did was successful.

IMAPClient actually uses imaplib internally. This may change at some point in the future.

Installing IMAPClient

IMAPClient is listed on PyPI and can be installed with uv:

uv add imapclient

More installation methods are described in the documentation.

Documentation

IMAPClient’s manual is available at http://imapclient.readthedocs.io/. Release notes can be found at http://imapclient.readthedocs.io/#release-history.

See the examples directory in the root of project source for examples of how to use IMAPClient.

Current Status

You should feel confident using IMAPClient for production purposes.

In order to clearly communicate version compatibility, IMAPClient will strictly adhere to the Semantic Versioning scheme from version 1.0 onwards.

The project’s home page is https://github.com/mjs/imapclient/ (this currently redirects to the IMAPClient Github site). Details about upcoming versions and planned features/fixes can be found in the issue tracker on Github. The maintainers also blog about IMAPClient news. Those articles can be found here.

Discussions

Github Discussions can be used to ask questions, propose changes or praise the project maintainers :)

Working on IMAPClient

The contributing documentation contains information for those interested in improving IMAPClient.

IMAP Servers

IMAPClient is heavily tested against Dovecot, Gmail, Fastmail.fm (who use a modified Cyrus implementation), Office365 and Yahoo. Access to accounts on other IMAP servers/services for testing would be greatly appreciated.

Interactive Console

This script connects an IMAPClient instance using the command line args given and starts an interactive session. This is useful for exploring the IMAPClient API and testing things out, avoiding the steps required to set up an IMAPClient instance.

The IPython shell is used if it is installed. Otherwise the code.interact() function from the standard library is used.

The interactive console functionality can be accessed by running the imapclient-interact script that is installed alongside IMAPClient, or by invoking the interact module like this:

uv run python -m imapclient.interact ...

“Live” Tests

IMAPClient includes a series of live, functional tests which exercise it against a live IMAP account. These are useful for ensuring compatibility with a given IMAP server implementation.

The livetest functionality is run using the imapclient-livetest script that is installed alongside IMAPClient:

uv run imapclient-livetest <livetest.ini> [ optional unittest arguments ]

The configuration file format is described in the main documentation.

WARNING: The operations used by livetest are destructive and could cause unintended loss of data. That said, as of version 0.9, livetest limits its activity to a folder it creates and subfolders of that folder. It should be safe to use with any IMAP account but please don’t run livetest against a truly important IMAP account.

Please include the output of imapclient-livetest with an issue if it fails to run successfully against a particular IMAP server. Reports of successful runs are also welcome. Please include the type and version of the IMAP server, if known.