vdirsyncer

vdirsyncer is a command‑line utility that synchronizes calendar and address‑book data between remote CalDAV/CardDAV servers and the local filesystem. It can keep a local directory in sync with a server, allowing other programs to edit the files and then push those changes back, or it can directly replicate data between two servers without involving a client. The tool is intended for users who need reliable, bidirectional sync of calendar events and contacts, similar to how OfflineIMAP works for email.

The software is distributed as a stable, BSD‑licensed package and is available for installation from the Python Package Index as well as Debian repositories. Documentation, tutorials, and contribution guidelines are hosted on Read the Docs, and the project maintains continuous‑integration status badges and code‑coverage reports.

vdirsyncer can be run in a Docker container through an unofficial image maintained by a community contributor, providing an isolated environment for users who prefer containerized execution.