DavMail
Exchange and Microsoft 365 gateway for standard mail and PIM protocols
752 stars 108 forks last commit first released GPL-2.0
Actively maintained
Last commit 24 Aug 2026.
DavMail is a gateway that exposes standard email, calendar, contacts, and directory protocols in front of Microsoft Exchange and Microsoft 365. It enables common clients to work with Exchange by translating IMAP/POP/SMTP, CalDAV/CardDAV, and LDAP requests to the underlying Exchange web interfaces.
Key Features
- IMAP and POP access to Exchange mailboxes (folder browsing via IMAP; inbox retrieval via POP)
- SMTP submission for sending mail through the gateway
- CalDAV support for calendars, including attendee scheduling and free/busy
- CardDAV support for syncing personal contacts
- LDAP gateway for Global Address List and personal contacts, enabling address auto-completion
- Cross-platform Java implementation, commonly used on Windows, Linux, and macOS
Use Cases
- Use Thunderbird, Apple Calendar/Contacts, or similar clients with Exchange without Outlook
- Provide CalDAV/CardDAV endpoints for devices and apps that do not speak native Exchange protocols
- Expose LDAP for directory lookups and recipient completion when composing email
DavMail is well-suited when you need standards-based interoperability with Exchange environments, including scenarios where access is available via web endpoints such as Outlook Web Access.
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