There are open source alternatives for most apps, but you might not even be aware of the free and open source alternatives to Google Calendar. If you are unfamiliar with the idea of open source, the basic concept is that the source code is available to everyone, so installing an open source calendar app prevents tracking or sharing of your data in the app without your knowledge.
Google Calendar comes pre-installed on most Android phones and is a complete solution that offers seamless integration with other Google services. However, if you don’t want to share your information with Google and want to keep your schedule private, there are several open-source alternatives available for Android.
Why open source matters
Free and open source software (FOSS) has a number of advantages, but for most people the biggest advantage is privacy. All the code is open, so anyone with programming knowledge can walk through it and see exactly what an app does. Proprietary apps can sometimes feel like black boxes, where you don’t really know what’s going on behind the scenes. This is rarely the case with FOSS.
We say “almost” because nothing technically prevents open source applications from spying on you, but this behavior is extremely 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.
A lot of people just prefer open source apps on principle, the same way some people prefer to shop at local stores over Walmart or Target. These apps are often created by individuals or small groups in their spare time, unlike large companies whose revenue is generated through advertising or venture capital.
Simple Mobile Tools offers a brilliant range of open-source apps, and its calendar app gives you everything you need, including a search feature, widgets, reminder notifications, multi-calendar support, no advertising, etc. If you want to use local calendars, you can import and export .ics files with just a few clicks.
Simple Calendar offers a free app that includes all the features I mentioned earlier, but the Pro version has more notification and invitation options. Its interface is similar in all simple applications, so it is an ideal solution if you want to use a unified suite of open source applications. The app can also sync calendars from any app on your phone.
Etar is another great open source option. It’s lighter on features than Simple Calendar, but still has month/week/day/agenda views, light and dark themes, notification support, no ads, and a clean design. Like Simple Calendar, it can pull calendars from Android’s built-in CalDAV service, so my Google Calendar schedules popped up effortlessly. You can also import and export calendars in .ics format.
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. It lacks features found in other calendar apps like Notes, and the ability to import data from other calendar apps. However, 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. .
DAVx⁵ is not a calendar app per se – rather it acts as a synchronization 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 a CalDAV provider for the Android system, most contacts/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.