Self-hosted apps that integrate with Microsoft Exchange

5 open-source, self-hostable projects list Microsoft Exchange as an integration.

• SOGoSelf-hosted, open-source groupware server: webmail, calendars and address books, with native client access via CalDAV, CardDAV, IMAP, SMTP and Microsoft ActiveSync.
• DavMailDavMail is a self-hosted, open-source gateway letting any mail client access Microsoft Exchange and Office 365 via IMAP, SMTP, CalDAV, CardDAV, and LDAP.
• calrscalrs is an open-source, self-hosted Rust scheduling platform for CalDAV, Google Calendar, and Exchange. Define bookable meetings, share links — single binary with SQLite
• seatsurfingSelf-hosted desk booking platform with interactive floor plans, approval workflows, Teams/Confluence integrations, and a PWA for mobile access.
• TymeslotSelf-hosted open-source meeting scheduler that syncs calendars, creates video rooms, and embeds booking pages — all free when you run it yourself.