Mailr is an open source webmail application written in Ruby which uses Ruby On Rails web application framework. The application is tested with Courier-IMAP but it should be possible to use it with any other IMAP server.

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Features
- Uses IMAP protocol
- Caches IMAP server connections
- HTML and plaintext message composition
- Addressbook (contacts) with possible import from CSV file
- Ajax based autocomplete of email addresses
- Mail filters based on Maildrop
- i18n based on Sascha Ebach's manual