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.

Your calendars and contacts do not need a cloud account, and Baikal is the small PHP server that keeps them on hardware you control while still syncing to every phone and laptop you own. The web admin panel is where you add users, create their calendars and address books, and reset passwords, no database editing or config files required. Each person signs in with their own username and password, so an iPhone, an Android phone running DAVx5, and a Thunderbird desktop can all stay in sync without sharing one master credential. Standard well-known redirects mean most clients configure themselves when you type the server address, and the combined dav.php endpoint serves calendars and contacts from a single URL. Events carry the full CalDAV feature set your clients expect (recurring appointments, reminders, attendees, and free-busy lookups), while CardDAV address books keep names, phone numbers, and photos in one place. Because storage is a plain database file or table set, backups are a copy you can make in seconds, and moving to a bigger host is a file transfer rather than a migration project. The same server happily runs for one person tracking a family calendar or for a small office sharing team schedules and a company address book. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL-3.0 licensed.

Mitra is a self-hosted calendar that puts your tasks on the same timeline as your events, so planning a week finally happens in one place instead of two. Drag across empty grid space to make an entry, drag it to move it, and stretch its edges to resize it. Tasks without a date sit in the Planning tab with a due date and an estimate until you drag them into the week. Subtasks and dependencies draw as lines between entries. Availability shading lays your working hours under the grid so double-booking becomes obvious before it happens. Keep calendars inside Mitra with no account behind them, or connect the ones you already use: CalDAV, Google Calendar, Apple Calendar, Notion, Todoist, and Tempo all sync both ways, and published feeds arrive as read-only subscriptions. Lists sort, filter, and change many entries at once. Files attach to entries, guests reply, reminders land as push notifications, and a command palette drives everything from the keyboard. Claude, Cursor, and other AI tools can read and plan your calendars over MCP. Eight languages, right-to-left layouts, light and dark themes, phone install, and OIDC sign-in for several people round it out. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

SOGo adds shared calendars, address books, and a modern webmail interface to your existing Dovecot, Postfix, or Cyrus mail setup, turning familiar infrastructure into a full Exchange competitor. Rather than replacing your IMAP and SMTP servers, SOGo layers collaboration on top of them, becoming the missing link between raw mail delivery and what users actually expect from a workplace communication platform. The ActiveSync implementation synchronizes email, contacts, calendars, and tasks natively with iPhones, Android devices, and Windows without requiring users to manually configure CalDAV endpoints. CalDAV and CardDAV compliance ensures Apple Calendar, Thunderbird (via the official SOGo Connector extension), GNOME Evolution, and Android via DAVx5 all connect without plugins or workarounds. The web interface uses AngularJS Material design with responsive layouts, offering folder management, drag-and-drop calendar scheduling, contact groups, resource booking, and delegation. Shared calendars support free-busy lookups, iMIP event invitations, and per-user ACL permissions for fine-grained access across organizational units. Built on Objective-C with the GNUstep foundation, SOGo delivers exceptional performance: hundreds of concurrent ActiveSync connections from mobile devices alongside webmail and calendar traffic with sub-second response times. With 2,095+ stars and 116 releases, the project has proven its stability in production environments supporting thousands of users. The Docker deployment runs alongside PostgreSQL and memcached.

Google Workspace and Microsoft 365, replaced by a platform you actually control: Nextcloud is the self-hosted digital workspace. Files is the core: file storage and sync across desktop, mobile, and web clients, with sharing, versioning, and collaboration built in. Around it, Talk provides private text chat, audio/video conferencing with screen sharing, SIP integration, and persistent voice rooms; Groupware bundles calendar, contacts, and mail with delegation support; and Office offers two collaborative suites - the Collabora-based option with deep ODF support, and Euro-Office, whose local-processing architecture delivers strong Microsoft Office compatibility and fast browser rendering with reduced server load. The Nextcloud Assistant threads AI through the platform via a context-aware sidebar, Whiteboard covers visual collaboration, Flow handles automation, and an app ecosystem of hundreds of extensions adds everything from Kanban boards to end-to-end encryption. Hub 26 brings a lighter UI with a unified app switcher and Nextcloud Governance for organizations under strict regulatory requirements. This is the flagship of data sovereignty: your files, chats, calendars, and documents live on your server, under your jurisdiction, with GDPR compliance by architecture rather than by contract.

Kurrier unifies email, calendars, contacts, and file storage in a single web interface that connects to any email provider you already use. The Next.js frontend with Nitro API worker deploys via Docker Compose on PostgreSQL and Redis, delivering a cohesive workspace where IMAP/SMTP mailboxes from Gmail, Outlook, or corporate servers sit alongside transactional providers like AWS SES, SendGrid, Mailgun, and Postmark. Automatic inbox building handles threads, attachments, sent items, and deletion sync through persistent background polling. The CalDAV backend enables full two-way calendar synchronization with iOS, macOS, Android via DAVx5, and Thunderbird, supporting event invitations, RSVP processing through the inbox, timezone-aware scheduling, and contact-aware attendee linking. CardDAV contacts sync bidirectionally across all devices with unified name, avatar, and email resolution. Kurrier Drive provides integrated file storage through WebDAV locally or S3-compatible backends for cloud storage. Multiple identities and domains let you manage several email accounts from different providers in one interface, with fast local search indexing subjects, senders, and content without dependency on external APIs. The API-first architecture exposes clean endpoints for automation and custom integrations. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

Five mailboxes, five tabs, five passwords: Gofer folds Gmail, Outlook, iCloud, and plain IMAP accounts into one browser tab where every inbox reads as a single, searchable whole. Threads, labels, and drag and drop keep triage fast, and search still finds the receipt from three years ago. Signatures and custom senders shape outgoing mail, scheduled sends wait for Monday morning, and a thread in another language translates in place. The calendar keeps pace with your mail: Google, Outlook, and CalDAV events sync both ways, invitations land in the inbox, and an RSVP or a Meet or Teams link attaches without leaving the message. Contacts follow the same rule through Google, Outlook, and CardDAV sync, so the address book you fix once is right everywhere. One install can serve a household or a small office, with separate users, encrypted credentials, blocked remote images, and passkey or authenticator sign-in for anyone who wants it. Classic, Minimal, and retro Express themes, flexible layouts, and push notifications make the daily inbox feel personal rather than administered. Leaving stays easy too: mailboxes export as mbox, mail moves between accounts, and a whole setup imports into another Gofer. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Unlike a calendar alert that rings on one phone, a MIND reminder reaches any of 100+ services, including email, Pushbullet, BlueSky, Cisco Webex Teams, and SMS gateways, from a self-hosted reminder app that you control. Normal reminders fire with second precision once or repeat every few days, once a year, on chosen weekdays, or on a custom cron schedule, while static reminders wait for a button press, so a single tap can tell the family that you are running late. Templates store colour, title, services, and text for fast creation, and the colour-coded library can be searched and sorted, with each reminder enabled, disabled, or tested on demand. Time zone changes, including daylight saving shifts, are accounted for, and sends that fail on a connection error are retried every two minutes until they succeed. Several users can share one instance: the admin panel handles accounts and registration, login lifetime, reverse-proxy URL prefix, debug logs, and scheduled database backups that can be exported and imported, and sign-in supports two-factor authentication. A documented REST API covers reminders, templates, notification services, and static triggers, and the web interface adapts to phone screens. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL-3.0 licensed.

Your family's shopping list, calendar, chores, meal plan, and budget share one home in OpenFamily, a self-hosted organizer that replaces subscription family apps with software you control. At the store, everyone ticks items off the same shopping list, with automatic categories, prices, reusable templates, and a store mode that groups items by category, and every phone updates instantly. At home, recurring tasks with three priority levels go to a specific family member, and in Pocket money, approved chores earn points that convert to payouts and savings goals. The calendar offers a monthly view per member, handles recurring and all-day appointments with up to five reminders each, follows Google, Outlook, or iCloud calendars by address, imports .ics files, and publishes its own iCal feed. Recipes can be found by typing the ingredients you already have, then dropped into a weekly meal plan. At month's end, the budget shows recurring income and expenses, per-category limits, charts, and a Kakeibo view. A kiosk display turns a wall tablet into a read-only board of today's schedule, meals, tasks, and who's where, alongside sticky notes from the family. Member profiles store allergies, vaccines, and emergency contacts, and parent and child roles keep the budget read-only for kids. Mealie, Tandoor, Home Assistant, Grocy, Nextcloud, and Immich connect in one click, and an optional AI assistant handles plain-sentence requests. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

OxiCloud is a self-hosted cloud for files, photos, calendars, contacts, and office documents. Drives can be personal or shared, with configurable storage quotas. Multi-gigabyte uploads travel as parallel, resumable chunks with integrity verification. Images, PDFs, audio tracks, and video streams preview right in the browser, and photos show EXIF details and map locations. Files sync over WebDAV. Calendars sync over CalDAV. Contacts sync over CardDAV. Desktop file managers, Thunderbird, Apple Calendar, and mobile DAVx5 clients connect without proprietary software. Collabora Online or OnlyOffice plug in through WOPI for real-time co-editing of spreadsheets, presentations, and text documents. Administrators enforce role-based access controls. Sign-in runs through OpenID Connect providers such as Keycloak, Authentik, or Azure AD. Public share links can carry a password and an expiration. Identical files are stored once, and adaptive compression keeps footprints compact. Local disks, Amazon S3, and Azure Blob can be mounted at the same time, with live background migration and automated consistency checks. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

A personal cloud does not need the weight of a small enterprise suite, and bewCloud proves it by keeping files, photos, notes, contacts, and calendars in one compact service a single person can run for a whole household. The Files app stores uploads in a plain folder tree on disk, offers public sharing links, optional whole-folder downloads as zip archives, and a WebDAV endpoint that desktop tools can mount. Photos turns that same storage into a browsable gallery, while Notes keeps quick text within reach of every login. Contacts and Calendar speak CardDAV and CalDAV through a bundled Radicale server, so the calendar and address book on a phone or laptop stay in sync without another account anywhere. News collects feeds to read in the browser, and Expenses tracks spending in a small ledger beside everything else. The header shows only the apps you enable, in the order you choose, and companion desktop and mobile apps connect to the same server for people who prefer native sync. Accounts can be protected with multi-factor authentication using TOTP, passkeys, or email codes, and optional single sign-on lets a household sign in through an existing identity provider. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

Take the tool sales teams use to never forget a client detail and point it at the people who actually matter - friends, family, the colleague whose kid's name you keep blanking on: Monica is a personal CRM. It's a Laravel/PHP application over MySQL where each contact accumulates the texture of a real relationship: how you met, family members and pets, work changes, addresses, notes from conversations, activities done together, gift ideas and gifts given, even debts owed in multiple currencies. Two features set it apart from every contact app. Reminders with staying power: set per-contact intervals (weekly through yearly), get notified at 30 days, 7 days, and day-of, with automatic birthday reminders and CalDAV sync to your calendar. And a journal linked to contacts: write about dinner with friends, tag each person, and build a timeline that's part diary, part relationship log - plus a daily "how was your day" rating. Monica is deliberately manual and deliberately private: no social network features, no AI, no email scraping, no ads, no analytics - a quiet database of what you know about people you love, on your own server. Multiple vaults and users, labels, custom activity types, and document/photo uploads round it out. AGPL-licensed.

Friends drift away when nobody remembers to call; Meerkat CRM is a self-hosted personal CRM that keeps your relationships warm with birthday and stay in touch reminders, contact notes, and a living map of who knows whom. Organize every contact into circles like family, friends, or work, store spouses and children as linked relationships, and see the whole crowd on an interactive network graph that shows how people connect. Sync the same address book two ways: Meerkat runs its own CardDAV server for your phone and can also act as a CardDAV client against an external server you already use. Against each person you can keep the details that matter, dietary habits, kids names, the last conversation, plus a social style timeline of activities you have shared, from dinners to group projects. Reminders nudge you by email when it has been too long, with upcoming birthdays surfaced on the dashboard, so catching up becomes a habit instead of an afterthought. Move data in and out freely: import CSV, VCF, and even a Monica export, export back to CSV and VCF, connect external calendars, and fire webhooks into your own automations. Use it in English, German, Italian, Spanish, or French with light and dark modes, and SSO for whoever shares the house. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Your contacts live in four different address books; Contrack merges Apple, Google, LinkedIn, and Facebook into one self-hosted personal CRM you fully control. Importing merges the address books you already keep, and connecting a calendar or inbox lays past meetings and conversations along each person's timeline. Obvious duplicates merge themselves, borderline matches wait in a side-by-side review with field-level differences highlighted, and every merge can be undone for 90 days. A scribbled note such as 'met at Sarah's wedding, catch up quarterly' turns into fields, tags, dates, and reminders, while optional web research fills in roles and links with cited sources. Each morning, Pulse shows who is due a follow-up, whose birthday lands this week, and which friends have quietly gone a year without contact. Ask Contrack answers plain questions like 'who do I know in Lisbon' or 'who loves natural wine' by searching your notes and contacts locally. The map plots everyone by city, and drawing a loop around a neighborhood before a trip turns a visit into a dinner list in seconds. Households share one server while each profile keeps a private book, and the built-in MCP server lets Claude, ChatGPT, or Cursor look up context and log notes for you. One-click verified backups snapshot the whole address book, passkeys handle sign-in, and open exports mean your data leaves whenever you do. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.