EteSync - Secure Data Sync

261 reviews
Content rating
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About this app

Secure, end-to-end encrypted, and privacy respecting sync for your contacts, calendars, and tasks (using and OpenTasks). For notes, please use the EteSync Notes application.

In order to use this application you need to have an account with EteSync (paid hosting), or run your own instance (free and open source). Check out for more information.

Easy to Use
EteSync is very easy to use. It seamlessly integrates with Android so you won't even notice you are using it. Security doesn't always have to come at a cost.

Secure & Open
Thanks to zero-knowledge end-to-end encryption, not even we can see your data. Don't believe us? You shouldn't, just verify yourself, both the client and server are open source.

Full History
A full history of your data is saved in an encrypted tamper-proof journal which means you can review, replay and revert any changes you have made at any point in time.

How does it work?
EteSync integrates seamlessly with your existing apps. All you need to do is sign up (or run your own instance), install the app, and enter your password. After that, you will be able to save your contacts, calendar events and tasks to EteSync using your existing Android apps, and EteSync will transparently encrypt your data and update the change journal in the background. More security, same work-flow.
Updated on
Mar 1, 2024

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
This app may collect these data types
Personal info, Calendar, and Contacts
Data is encrypted in transit
You can request that data be deleted

Ratings and reviews

256 reviews
A Google user
January 11, 2019
Excellent product and service. Well worth supporting the developer's work by subscribing. I tried rolling my own self-hosted caldav/carddav service using a couple different FOSS applications, but each had quirks I didn't want to deal with. EteSync has worked flawlessly for me, and eliminated the time I'd have to spend maintaining more server-side apps. Thanks for the great product!
43 people found this review helpful
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Liam Randall
August 24, 2023
Rapid summary: service does not recognize non mainstream (Google, Apple) calendars and contact books - won't sync. File-based syncing cannot be automated. Doesn't seem to be any data recovery functionality. How are you supposed to get your saved data on your recovery device?? App won't parse .ics files if they're too big. The app has long roads to get to being useful.
9 people found this review helpful
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August 24, 2023
I think you have a misconception about what this product does, it doesn't recognize any mainstream or non-mainstream calendars, it works with its own... Too big of an ICS: first time we are hearing about it, but a quick workaround would be cutting it in two and trying that?
Kaine Inja
November 30, 2020
I want to like this app on principle, but it just doesnt work properly for me. Set up and initial sync of contacts seems to work fine, can see in contacts app, but after some time the contacts app just shows an empty address book even tho the sync journal shows the contacts have synced & should be there. I have tried clearing data, reinstalling, same thing happens every time. I use a self hosted server rather than the paid service, so maybe this app just doesnt work so well with custom servers.
29 people found this review helpful
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November 30, 2020
Sorry to hear about your issue! This is definitely not how it should work. It has nothing to do with using a self-hosted server as those are essentially identical to the hosted ones. Please come to the chat at we would be happy to help figure out what's wrong!

What's new

* Fix error when importing from file in Android 13+