Calendars, to-do lists, journal entries, and contacts, synced over the open CalDAV and CardDAV standards nearly every client already speaks: Radicale is a small pure-Python server that works with Thunderbird, DAVx5 on Android, Apple Calendar and Contacts, GNOME, and many more. Its defining design choice is radical simplicity: there is no database. Events live as plain .ics files and contacts as .vcf files in an ordinary folder structure, which makes backup a copy command, migration a move, and disaster recovery a matter of reading text files. The server works out of the box with no complicated setup, then grows as needed: flexible authentication (htpasswd files among other methods), per-collection authorization rules, TLS-secured connections, and a plugin system for extending storage, auth, and rights handling. Built-in limits on parallel connections, file sizes, and failed authentication attempts harden it for network exposure behind a reverse proxy. A bundled web interface handles creating and managing calendars and address books - useful since many clients cannot create collections themselves. Maintained since 2011 with 140+ contributors, GPLv3-licensed, and light enough to run on the smallest VPS or a Raspberry Pi.

Replace a dozen household subscriptions with one app that keeps your family's tasks, calendars, meals, budget, and shopping in a single private place you control. Nineteen modules cover the daily rhythms of a household: assign chores with deadlines and priorities, plan the week's dinners and push the ingredients to a shared shopping list in one tap, track income and expenses by category with automatic subscription renewal warnings, and log health activities from vitals to medications. Two-way sync connects to Google Calendar via OAuth, iCloud and Nextcloud via CalDAV, and Outlook via Microsoft Graph, so every family member's phone shows the same schedule without switching apps. CardDAV keeps contacts in sync with external address books. The budget module handles accounts, loans, split expenses, and per-category planning with savings goals and month-over-month comparisons. Documents attach to tasks, receipts link to transactions, and a checked-off grocery item books itself back into the pantry inventory with its quantity. A Kanban board, recurring task schedules, and a rewards ledger that pays out points for completed chores keep kids and adults accountable. Wall mode turns a kitchen tablet into a glanceable family dashboard, and the Immich screensaver shows your own photos when the screen goes idle. API tokens and a built-in MCP endpoint let AI agents and third-party tools interact with every module programmatically. Deploy on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.