Rustical is an open-source CalDAV and CardDAV server written in Rust, providing a lightweight, self-hosted alternative for calendar and addressbook synchronization. It implements the core WebDAV extensions (RFC 4791, 6352) with support for CalDAV scheduling, CardDAV group membership, WebDAV Push (web-push) notifications, and a built-in web frontend for management. The architecture is a modular Rust workspace with separate crates for DAV infrastructure, protocol handlers (caldav, carddav), storage abstraction, SQLite backend, XML serialization, OIDC authentication, and a Lit-based web UI. The server exposes RESTful HTTP endpoints via Axum, uses SQLite for persistence with `sqlx`, and supports app tokens, OIDC, and Nextcloud login for authentication. The codebase demonstrates solid engineering with thorough integration tests, snapshot testing, CI/CD pipelines, and a clear separation of concerns. However, it contains some workarounds and TODOs indicating active development rather than a polished final product. The custom XML derive macros and store trait pattern are particularly well-crafted and potentially reusable.
python-o365 is a mature Python library that provides a comprehensive, object-oriented wrapper around the Microsoft Graph API. It enables developers to programmatically access and manage Microsoft 365 services including Outlook email and calendar, OneDrive and SharePoint files, Teams chats and presence, Planner tasks, directory users and groups, and more. The library abstracts OAuth2 authentication (supporting authorization code, public client, and client credentials flows) and handles token refresh, pagination, and API versioning internally. It is designed as a client-side SDK, not a server application, and can be embedded into scripts, web applications (e.g., Flask), or automation workflows.