OpenSync is a Open Source CalDAV/CardDAV (Contacts and Calendars) Sync for Android. it has been tested with Nextcloud Server. its integrates natively in Android calendar/contact apps. its a fork from opensource project DavDroid https://davdroid.bitfire.at/source/.

Forked from DavDroid Version 1.5.0.3-ose

OpenSync Source code is at https://github.com/deependhulla/opensync

Its licensed under the GPLv3 License. same as davdroid.

Its mine personal attempt to make a Android App for CalDAV/CardDAV for NextCloud (Server which I use), again a OpenSource Software. Its still Beta from my side as its some basic changes to orginal code of DavDroid. Would try to find time to add more into this app. This is noway to replace original DavDroid app or compete with them.

If you love this app, I would recommend you to support DAVdroid (the original app), please consider donating to DAVdroid or purchasing it.

Parts of OpenSync have been outsourced into these libraries (based on original davdroid):

• cert4android custom certificate management
• dav4android WebDAV/CalDav/CardDAV framework
• ical4android iCalendar processing and Calendar Provider access
• vcard4android VCard processing and Contacts Provider access

USED THIRD-PARTY LIBRARIES

Extra libraries are used (based on orginal davdroid) :

• dnsjava BSD License
• ez-vcard New BSD License
• iCal4j New BSD License
• okhttp Apache License, Version 2.0
• Project Lombok MIT License