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The Best Open Source Alternatives to Google Calendar

Taking essential steps to improve your digital privacy is pointless if you continue to use Google’s apps. Using open source alternatives is essential to keep your data safe, as none of your data in the app can be tracked or shared without your knowledge.

Google Calendar is a great calendar app. Still, there are plenty of open-source alternatives available for Android. If you’re willing to sacrifice some features, these apps should meet most of your calendaring needs. If you just bought a new Android phone, install one immediately to protect your data.


Why open source matters

Free and open source software (FOSS) has several advantages, but for most people the main advantage is privacy. All of the code is open, so anyone with programming knowledge can walk through it and see what an app is doing behind the scenes. Proprietary apps are black boxes where you don’t know what’s going on behind the scenes.

Nothing prevents open source applications from spying on you, but this behavior is rare. If a developer does something they’re not supposed to, like spying on users or bundling malware, they probably won’t announce it to the world.

Simple calendar

Simple Mobile Tools has a brilliant range of open-source apps, and its calendar app is one of the best. The free version provides you with everything you need, including search function, widgets, reminders notifications, multi-calendar support, no ads, etc. If you want to use local calendars, you can quickly import and export .ics files.

While the free version of Simple Calendar has the basic features you need, the Pro version has more notification and invitation options. We recommend updating if you use the app regularly.

Simple Calendar’s interface is similar across all simple apps, so it’s an ideal solution if you want to use a unified suite of open-source apps.


Etar is another great open source option. It is lighter on features than Simple Calendar. Still, it has month, week, day, and agenda views, as well as light and dark themes, notification support, no ads, and a clean design. You can also import and export calendars in .ics format or import calendars directly from Google Calendar.

Proton calendar

Proton Calendar is developed by Proton Technologies, which has also developed a privacy-focused messaging app. Proton Calendar is developed with the same idea in mind, offering zero ads and tracking, end-to-end encryption, and zero data sharing.

However, it lacks common features found in other calendar apps, such as notes, and the ability to import .ics files. Still, it’s perfect for those who aren’t heavy users of calendar apps, as it includes the most important features like event notifications, a calendar widget, daily and monthly views, and recurring events. . Upgrade to the paid version to manage up to 20 calendars.


DAVx⁵ is not a calendar application per se. Instead, it acts as a sync server for other calendar and contacts apps to access cloud accounts. If you regularly switch devices, this can sync your calendar without the need to use Google Play Services.

DAVx⁵ can extract data from most cloud services including iCloud, Google, Nextcloud/OwnCloud, Fastmail, Synology DSM, Yahoo and many more. Because it acts as the CalDAV provider for the Android system, most contacts and calendar apps should be able to access it, including the ones that come with your phone.

There is no shortage of alternatives to open source applications

The limited range of open-source calendar apps on Android can be frustrating. However, many open-source email apps include calendar functionality, so it’s worth trying one out instead of a dedicated calendar app.