EteSync - Secure Data Sync

EteSync - Secure Data Sync

Secure, private and end-to-end encrypted calendar, contacts and tasks sync

Calendar & Agenda Internet Security System

Screenshots

Screenshot of EteSync - Secure Data Sync Screenshot of EteSync - Secure Data Sync Screenshot of EteSync - Secure Data Sync Screenshot of EteSync - Secure Data Sync

Description

Secure, end-to-end encrypted, and privacy respecting sync for your contacts, calendars, and tasks (using Tasks.org 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 https://www.etesync.com/ for more information.

Easy to Use
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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
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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
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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?
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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.

Versions

Version Date Size Requires Android Download
2.7.0 current
1ba72af98c30a790…
2026-03-09 11 MB API 21
2.6.0
f92a3bdb3ef79108…
2025-10-23 11 MB API 21
2.4.4
a84a94bd17857b43…
2024-03-09 11 MB API 21

Permissions

What the app asks the system for. Android only grants sensitive access after you confirm it.

  • Network stateCheck whether and how the device is connected.
  • Wi-Fi stateRead information about the Wi-Fi connection.
  • Internet accessSend and receive data over the internet.
  • Sync settingsRead synchronisation settings.
  • READ_SYNC_STATS
  • Change syncTurn synchronisation on and off.
  • REQUEST_IGNORE_BATTERY_OPTIMIZATIONS
  • NotificationsShow notifications.
Show 13 more permissions
  • AUTHENTICATE_ACCOUNTS
  • Accounts on the deviceRead the list of configured accounts.
  • MANAGE_ACCOUNTS
  • Write storageCreate and change files on the device storage.
  • Read storageRead files on the device storage.
  • Read contactsAccess the address book.
  • Change contactsCreate and change address book entries.
  • Read calendarRead appointments.
  • Change calendarCreate and change appointments.
  • permission.READ_TASKS
  • permission.WRITE_TASKS
  • permission.READ_TASKS
  • permission.WRITE_TASKS

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