RustiCal
Self-host calendar and contact synchronization with CalDAV and CardDAV.
RustiCal is a self-hosted CalDAV and CardDAV server for synchronizing calendars and address books with compatible clients. It stores data in SQLite and includes a web frontend, calendar import and export, OpenID Connect login, and group-based sharing.
The server and its protocol and storage crates are written in Rust, using Axum, Tokio, and SQLx. The project is under active development, and its maintainers warn that bugs and rough edges remain.