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7 self-hosted options

Open-source alternatives to Google Calendar

The best open-source alternative to Google Calendar is Nextcloud (AGPL-3.0, 37,298 GitHub stars). Radicale stands out for its Python codebase, and Baïkal follows.

About Google Calendar: Google's online calendar with sharing and event invites.

Updated · data from GitHub, refreshed daily

Top picks

  1. Rank 1:

    Nextcloud

    nextcloud/server

    Access and share your files, calendars, contacts, mail and more from any device, on your terms.

    Active · last commit Oct 26, 2026

    FeaturedFile Sync & StoragePHP

    Stands out for the most GitHub stars.

  2. Rank 2:

    Radicale

    Kozea/Radicale

    Simple calendar and contact server with extremely low administrative overhead.

    Active · last commit Oct 25, 2026

    Groupware & CalendarsPython

    Stands out for its Python codebase.

  3. Rank 3:

    Baïkal

    sabre-io/Baikal

    Lightweight CalDAV and CardDAV server based on sabre/dav.

    Active · last commit Oct 19, 2026

    Groupware & CalendarsPHP

At a glance

Google Calendar alternatives compared

Open-source apps come first, then source-available ones and apps whose license appsgit could not verify; within each group, projects with at least 12 commits in the last 12 months come before less active or archived ones, then by GitHub stars.

Google Calendar alternatives compared, data as of 2026-10-26
AppStands out forLicenseGitHub starsCommits (12 mo)Last commitDocker image
Nextcloudthe most GitHub starsAGPL-3.037,2988,041Oct 26, 2026No
Radicaleits Python codebaseGPL-3.05,1451,653Oct 25, 2026No
Baïkal–GPL-3.03,34932Oct 19, 2026No
SOGoits Objective-C codebaseGPL-2.02,176111Oct 22, 2026No
SabreDAVa permissive BSD-3-Clause licenseBSD-3-Clause1,72777Oct 1, 2026No
Davis–MIT76176Oct 25, 2026No
Xandikos–GPL-3.0610506Oct 21, 2026No

Full list

All 7 Google Calendar alternatives

Open any app for live stats, license details and a deploy option.

  1. 1

    Nextcloud

    Access and share your files, calendars, contacts, mail and more from any device, on your terms.

    Stands out for the most GitHub stars. Nextcloud has 37,298 GitHub stars, uses the AGPL-3.0 license and had 8,041 commits in the last year.

  2. 2

    Radicale

    Simple calendar and contact server with extremely low administrative overhead.

    Stands out for its Python codebase. Radicale has 5,145 GitHub stars, uses the GPL-3.0 license and had 1,653 commits in the last year.

  3. 3

    Baïkal

    Lightweight CalDAV and CardDAV server based on sabre/dav.

    Baïkal has 3,349 GitHub stars, uses the GPL-3.0 license and had 32 commits in the last year.

  4. 4

    SOGo

    SOGo offers multiple ways to access the calendaring and messaging data. CalDAV, CardDAV, GroupDAV, as well as ActiveSync, including native Outlook compatibility and Web interface.

    Stands out for its Objective-C codebase. SOGo has 2,176 GitHub stars, uses the GPL-2.0 license and had 111 commits in the last year.

  5. 5

    SabreDAV

    Open source CardDAV, CalDAV, and WebDAV framework and server.

    Stands out for a permissive BSD-3-Clause license. SabreDAV has 1,727 GitHub stars, uses the BSD-3-Clause license and had 77 commits in the last year.

  6. 6

    Davis

    A simple, dockerizable and fully translatable admin interface for sabre/dav based on Symfony 5 and Bootstrap 4, largely inspired by Baïkal.

    Davis has 761 GitHub stars, uses the MIT license and had 76 commits in the last year.

  7. 7

    Xandikos

    Open source CardDAV and CalDAV server with minimal administrative overhead, backed by a Git repository.

    Xandikos has 610 GitHub stars, uses the GPL-3.0 license and had 506 commits in the last year.

FAQ

Google Calendar alternatives: FAQ

Still curious? Email info@appsgit.com.

Is there a free alternative to Google Calendar?

Yes. All 7 apps on this page are open source and free to self-host, so you can replace Google Calendar without per-user fees. You pay only for the server.

Can I self-host an alternative to Google Calendar with Docker?

None of the apps here publishes a Docker image in the catalog data; install them from their own packages or source, following each project's guide.

Which Google Calendar alternative is the most actively developed?

Nextcloud (AGPL-3.0), with 8,041 commits in the last 12 months. Activity is a good sign that bugs and security issues get fixed.

How is this list ranked?

Open-source apps come first, then source-available ones and apps whose license appsgit could not verify; within each group, projects with at least 12 commits in the last 12 months come before less active or archived ones, then by GitHub stars.