EteSync is a journaled end-to-end encrypted contacts and calendar provider for all major platforms. Or to put it more plainly, it's an app that backs up and syncs your contacts and calendars across devices and to the cloud in a secure way while maintaining a full history of the changes. After setup, you won't even know it's there. You just keep on using the same contacts and calendar apps you were using before.

The name EteSync comes from End-to-End (Encrypted) Synchronization. Ete (or été) also means Summer in French. This is why the logo is a summer sun with blue (like the sea) synchronisation arrows.

Our servers are located in Austria and are hosted by EDIS, so our server is safe, but the beauty of EteSync is that you don't need to trust the server.

Please take a look at the FAQ entry for more information.


We believe in privacy as a basic right, and we believe end-to-end encryption is the best way to ensure this right for everyone. We would like to foster an ecosystem of secure, journaled applications that are as easy, if not easier to use than their insecure counter-parts.

Who are we?

EteSync was created by Tom, aka tasn, (more info on his website) because he was frustrated with the lack of secure solutions for contacts and calendar sync or even backup. For a short while there was Flock by the people behind Signal, but unfortunately it didn't last long.

Tom, as a long time open source contributor, privacy fanatic and previously a lead developer for SHR, the biggest Openmoko (the most free phone to have existed so far), decided to take matters to his own hands and create EteSync.


The best way to contact us is by joining our chat room, which you can access through our web chat, IRC channel (#etesync on, or Matrix room.

If you would like to contact us regarding a private matter, you can do so by email. If your email contains sensitive or private information, please encrypt it using the PGP with the key listed below.

We are also on Twitter (@EteSyncHQ), Mastodon ( and reddit (r/EteSync).

Code of Conduct

Click here for more information on our code of conduct.


For secure email, or verifying our signed releases, please use the following key: 0x9E21F091FC395F366A4743E2D2E584C37C477933


Interested in writing about us, or would like to learn more?

Please email us at

Screenshots are available at the user guide.
More resources: brand image (vector), logo (vector), and logo (png).

Credit and Attribution

The codebase for the EteSync client started as a fork of DAVdroid, a CalDav and CardDav sync adapter for Android. It has been heavily modified, but a lot is still based on, if not entirely the same as the original work. Many thanks to their great work and for releasing their code under the GPL. It would have taken us significantly longer to release this, and the result would have probably been much buggier without them. Please check out the about page in the app for more information about used third-party open source libraries.

This website, and the API server were built using django and many great open source django modules. The frontend uses Bootstrap for the CSS and the icons are either from Font Awesome or from the Material Design Icon Set.


We are proudly supported by the NLnet Foundation (courtesy of NGI0 Discovery and the European Commission DG CNECT's Next Generation Internet programme) and Svix - Webhooks as a service. For a quick overview of the Svix service, check out the Svix docs and their sending webhooks guides (Python, NodeJS, Rust, PHP).

The following individuals have contributed to EteSync in one way or another. Be it translations, patches or other contributions that have helped making EteSync better. This list is incomplete, so please, if you should be here and aren't, let us know!

Warrant Canary

What is this?

Hash: SHA256

As of today, 2024-07-07, EteSync has not been compromised. No backdoor has been
placed and no known security breach has been left unfixed.
In addition, EteSync has not recieved any requests to disclosue any information
about its users or been compelled to provide such.

A reminder: even if at some point we will be compelled to disclose such
information, we have almost nothing to share thanks to the nature of end-to-end
Please read the FAQ for more information and security tips.

This canary should be updated and signed every two months.