Cal.diy
Calendar & ContactsOnline appointment scheduling system
Replaces Calendly, Doodle
Best Multi-User Calendar & Contacts for self-hosting
The 22 best Multi-User calendar & contacts you can self-host, ranked by community traction.
OpnForm
Calendar & ContactsBeautiful open-source form builder
EteSync
Calendar & ContactsEnd-to-end encrypted sync for contacts and calendars
Replaces Google Calendar, iCloud
Bracket
Calendar & ContactsFlexible tournament system to build a tournament setup, add teams,
Alf.io
Calendar & ContactsTicket reservation system
AgenDAV
Calendar & ContactsCalDAV web client with an Ajax interface
Replaces Google Calendar
Claper
Calendar & ContactsThe ultimate tool to interact with your audience (alternative
DavMail
Calendar & ContactsPOP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway allowing users
Nextcloud Tasks
Calendar & ContactsCalDAV task list app for Nextcloud
Replaces Google Tasks, Todoist
OpenSlides
Calendar & ContactsPresentation and assembly system for managing and projecting agenda,
Manage My Damn Life
Calendar & ContactsManage my Damn Life (MMDL) is a self-hosted front end for managing
Framadate
Calendar & ContactsOnline polling and meeting scheduling tool
Replaces Doodle
Thunderbird Appointment
Calendar & ContactsSelf-hostable scheduling tool for booking meetings
Replaces Calendly, Doodle
hitobito
Calendar & ContactsManage complex group hierarchies with members, events and a lot more
ClearFlask
Calendar & ContactsCommunity-feedback tool for managing incoming feedback
Christmas Community
Calendar & ContactsCreate a simple place for your entire family to use to find gifts
Seatsurfing
Calendar & ContactsWebbased app to book seats, desks and rooms for offices
Bitpoll
Calendar & ContactsConduct polls about dates, times or general questions
Meetable
Calendar & ContactsMinimal events aggregator
Revel
Calendar & ContactsCommunity-focused event management and ticketing platform
Horde Kronolith
Calendar & ContactsCalendar application from the Horde groupware suite
Replaces Google Calendar, Exchange
Digistorm
Calendar & ContactsCreate collaborative surveys, quizzes, brainstorms, and word clouds
No apps match these filters.
At a glance
| App | Deploy effort | Difficulty | Min. RAM | License | ★ Stars |
|---|---|---|---|---|---|
| Cal.diy | Read-the-docs project | Medium | 512 MB | MIT | 48,984 |
| OpnForm | Under-an-hour setup | Medium | 512 MB | AGPL-3.0 | 3,833 |
| EteSync | Under-an-hour setup | Medium | 256 MB | AGPL-3.0 | 1,773 |
| Bracket | Under-an-hour setup | Medium | 512 MB | AGPL-3.0 | 1,742 |
| Alf.io | Read-the-docs project | Medium | 512 MB | GPL-3.0 | 1,616 |
| AgenDAV | Under-an-hour setup | Medium | 128 MB | GPL-3.0 | 831 |
| Claper | Under-an-hour setup | Medium | 512 MB | GPL-3.0 | 812 |
| DavMail | Read-the-docs project | Medium | 512 MB | GPL-2.0 | 766 |
| Nextcloud Tasks | Read-the-docs project | Easy | 512 MB | AGPL-3.0 | 707 |
| OpenSlides | Under-an-hour setup | Medium | 512 MB | MIT | 652 |
Quick picks
- Most adopted: Cal.diy (48,984 GitHub stars).
- Lightest footprint: AgenDAV (from 128 MB RAM, against 512 MB for the heaviest here).
- Licensing: 8 of 22 use AGPL-3.0; check the rest individually if you plan to modify and redistribute.
Every option here is open-source and self-hostable, tagged Multi-User within the calendar & contacts category. Deploy effort is graded from published container recipes, not vendor claims — see the methodology.