Service businesses get a booking page without per-booking commissions or monthly SaaS fees from Easy!Appointments, the self-hosted appointment scheduler. Customers pick a service, provider, and open time slot from a clean web form; the system enforces working plans, breaks, and booking rules you define per provider, then confirms by email to both sides. The structure fits real service organizations: multiple providers with individual schedules, multiple service types with their own durations and prices, and admin/secretary roles for front-desk management. Two-way Google Calendar synchronization keeps each provider's external calendar authoritative - book in Easy!Appointments and it appears in Google Calendar, block time in Google and the slot disappears from the booking form. Version 1.6 adds SMS notifications and payment support, and a REST API opens the scheduling data to custom integrations. Built on PHP (CodeIgniter) with MySQL, it installs in a single folder and can share a database with your existing site; a WordPress plugin embeds the booking form directly in pages or posts. The interface ships in dozens of languages with time-zone handling throughout. GPL-3.0 licensed and free for commercial use - a helpdesk, clinic, salon, or consultancy runs its whole booking workflow on its own server.

Built on Elixir's fault-tolerant OTP runtime, Tymeslot delivers the complete scheduling toolkit that Calendly charges for and Cal.com relicensed away from open source in 2026. Share one booking link and let clients pick available slots — your calendar stays synchronized and double-bookings disappear automatically through real-time availability checking against Google Calendar, Microsoft Outlook, and any CalDAV server including Nextcloud. Meeting types support configurable durations, buffer times, and availability windows that clients can book without email back-and-forth. Phoenix LiveView powers the real-time UI with WebSocket connections that update instantly as bookings arrive, without client-side JavaScript framework overhead. The platform attaches Zoom video rooms to confirmed bookings through your own Marketplace app credentials, sends confirmation and reminder emails via SMTP, Postmark, SendGrid, Mailgun, or AhaSend, and supports custom booking page themes with embed options for integration into existing websites. Circuit breakers, connection pooling, and graceful degradation maintain availability during provider outages. Authentication supports local accounts, GitHub OAuth, and reCAPTCHA protection on public booking forms. Self-hosting deploys as a single container with PostgreSQL embedded — no separate database container required. Two named volumes persist uploads and database state, while the same image powers the managed cloud at tymeslot.app so self-hosted users get identical features without a crippled community edition. Deploy via Docker, Cloudron with automatic updates, or Railway from a community template. 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.

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.

Scheduling infrastructure, not just a booking page - Cal.com is the leading open-source scheduling platform. Share a link, attendees pick a slot, and real-time sync against Google Calendar, Outlook, and CalDAV prevents double-booking. Beyond the basics it covers team workflows: round-robin distribution, collective availability across multiple hosts, recurring meetings, and routing forms that ask bookers questions and send them to the right team member - the feature sales and support teams usually pay enterprise prices for. Paid bookings run through Stripe, video calls through the built-in Cal Video (Daily.co) or Zoom and Google Meet, and an app store connects 100+ tools including HubSpot, Zapier, and n8n. The API-first architecture with webhooks and embeds makes it practical to build scheduling into your own product, white-labeled with your domain and branding. Built on Next.js and Prisma over PostgreSQL, translated into 65+ languages, with the self-hostable community codebase maintained under an open-source license.

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.

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.

TryPost is an open-source social media scheduler that publishes natively to thirteen networks from one composer, calendar, and queue, whether the author is a person on your team or an AI agent connected over MCP. Write a post once and it adapts per network, with a live preview of each version, character quirks handled, and an AI assistant in the editor to rephrase, shorten, or expand when a caption fights back. Posts land on each channel's own posting times in its queue, the calendar shows the whole month at a glance, and anything can be dragged to a new slot when plans change. Members who need a second opinion send work for approval, and admins approve or reject in one click, which is how agencies keep many brands from becoming many headaches. Workspaces keep every client apart with its own channels, members, and settings, while signatures save the hashtag and call-to-action blocks you refuse to retype and labels color-code the calendar. Insights follow followers and post performance across channels, Repurpose copies videos you posted elsewhere onto your other networks automatically, and webhooks announce every created, published, or failed post to your other tools. 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.

GroupOffice checks your whole company in at one address: mail, meetings, projects, invoices, and files behind a single login on your own server. The built-in mail client saves messages straight onto projects or contacts, signs and encrypts with S/MIME, and shares folders and accounts across the team. Shared calendars offer team views, bookable resources, and video meetings, while address books carry custom fields and comments so customer knowledge survives staff changes. Projects gather their tasks, files, and discussions in one place, track hours as work happens, and turn those hours and costs into invoices and reports. Support tickets arrive from your website or by email and stay organized by team, and newsletters compose campaigns from templates filled with your own data. Files co-edit in the browser through OnlyOffice or Collabora, connect to desktops over WebDAV, and sync to native phone and computer apps over open protocols. Two-factor authentication, encryption, and a module system you can extend with your own tools keep the office private and shaped to how you actually work. 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.

Dobase replaces the scattered pile of team subscriptions with one self-hosted workspace where mail, kanban boards, documents, chat, to-do lists, files, a calendar, and video rooms live side by side. Install only the tools your team needs, and share each one with exactly the collaborators you choose; a board for the whole company and a private todo list can sit in the same window. Several people can type in the same document at once, watching each other's colored cursors while the text merges cleanly, and presence faces in the sidebar show who is inside every tool right now. Open tools arrange themselves as tiles in a wide window, so chat can sit next to the board it discusses and the calendar under the mail you are answering. Pressing Cmd+K searches cards, todos, documents, files, chat, events, and mail in one motion, and nearly everything also works from the keyboard alone. Mail threads conversations and lets you accept calendar invites from the message, files get public links guarded by a password and an expiry, and the calendar syncs with CalDAV services or runs on its own. Video rooms with screen sharing join the same workspace, mentions and notifications follow you, and an email digest catches up anyone who was away. 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.

Work, personal, business, and school calendars at different providers double-book because no one system sees your real availability - Keeper solves that multi-calendar collision problem. Its pull-compare-push sync engine aggregates events from Google Calendar, Outlook/Office 365, iCloud, FastMail, any CalDAV server, or read-only iCal/ICS feeds, and pushes blocking events to one or many destination calendars so time slots align everywhere. The design is deliberately content-agnostic - it syncs timeslots, not titles or descriptions, so a personal appointment shows as busy time on your work calendar without leaking details. Sync logic is clean: events Keeper creates carry a traceable UID suffix, deletions propagate, and orphaned entries are purged automatically. A token-authenticated aggregated iCal feed combines selected calendars into one subscribable URL for Apple Calendar or Thunderbird. An optional MCP server gives AI agents read-only calendar access over OAuth 2.1 - list calendars and query events by date range, with no write capability. Built with Next.js and Bun under AGPL-3.0, the standalone Docker image bundles web, API, cron, worker, Redis, and PostgreSQL in one container, and self-hosting unlocks every Pro feature - unlimited calendars and one-minute sync intervals - for free.

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.

Conference rooms, equipment, boats, and even people can be reserved through LibreBooking, a self-hosted scheduler that keeps double bookings off the calendar. Schedules define bookable time slots with custom layouts and seasonal availability, while each resource carries its own minimum and maximum duration, buffer time, lead time, capacity, and optional approval step. Check-in and check-out can release unclaimed slots automatically, and blackout times close resources for maintenance. Quotas stack limits by hours or reservation count, credits meter peak and off-peak usage, and users can buy credits through Stripe or PayPal. Accessories such as projectors or chairs ride along with a booking under their own quantity limits. Groups carry application, group, resource, and schedule administrator roles, and custom attributes extend reservations, resources, and users with text, dropdown, date, or checkbox fields. Reports can be charted, exported to CSV, printed, or emailed, and public resources publish RSS and iCalendar feeds for Outlook and Thunderbird plus an embeddable calendar snippet. A tablet view beside a door shows live availability for on-the-spot booking, a monitor view fills lobby screens, and a Slack command starts a reservation. Sign-in options include LDAP, Active Directory, OAuth2, and SAML, and the REST JSON API automates bookings. Users can join waitlists, request reminder emails, and accept terms of service before booking, while six color themes restyle the interface. 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.

Consolidate daily to-do lists, encrypted passwords, household spending, contacts, and family photo galleries into Personal Management System, a self-hosted private command center for everyday life. Individuals can organize recurring schedules and calendar milestones with proactive notification alerts so important appointments, vehicle servicing dates, and recurring bill renewals are never overlooked. Users can balance household budgets and track expenditure across custom spending categories, calculating monthly cash flow balances while monitoring debts owed to friends or family members. Privacy-conscious users can safeguard account credentials inside an encrypted password vault featuring quick-copy buttons and secondary lock protection for sensitive personal entries. Goal setters can track multi-step personal targets and link financial milestones directly to dedicated savings pools. Home organizers can catalog contacts, log travel destinations with mapped imagery, and maintain categorized notes containing voice memos, bookmarks, and reference materials. Collectors can sort family photos and video recordings into interactive masonry galleries with built-in lightbox previews and file download tools. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT 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.

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.

With over 47,000 GitHub stars, Cal.diy is the fully open-source community fork of Cal.com that strips away every proprietary license gate and enterprise paywall to deliver a pure MIT-licensed scheduling platform you completely own. The booking engine supports individual event types including recurring events, seated events with capacity limits, and paid bookings through Stripe and PayPal, all backed by customizable availability schedules with date overrides, buffer times, minimum notice periods, and travel schedule support. Calendar synchronization is bidirectional across nine providers — Google Calendar, Outlook and Office 365, Apple Calendar, CalDAV, Lark, Feishu, Zoho, Exchange, and ICS feeds — so every booking automatically appears on your existing calendar while blocking conflicting slots. Video conferencing links generate automatically for Zoom, Google Meet, Microsoft Teams, Webex, Jitsi, Daily.co, Whereby, and Huddle01, eliminating manual link management. The automation layer connects through webhooks, Zapier, n8n, Make, and Pipedream to CRM platforms like HubSpot, Salesforce, and Close, messaging services including Discord, Telegram, and WhatsApp, and analytics tools such as Google Analytics 4, PostHog, and Fathom. The entire application is built on the T3 stack — Next.js for server-rendered pages, tRPC for end-to-end type-safe APIs, Prisma for PostgreSQL database access, and Tailwind CSS for the responsive interface. Unlike Cal.com's open-core model, Cal.diy requires no license key and includes no gated features. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

One calendar answers who is away next week: Urlaubsverwaltung is a self-hosted leave and absence manager where employees request vacation, managers approve it, and sick notes and overtime balances live beside the requests. A request moves through waiting, provisionally approved, finally approved, rejected, or cancelled states, so employees and approvers always see where a decision stands. Department heads decide for their own teams, a second stage authority can add the final approval, the boss sees every request company wide, and office staff manage people, settings, and sick notes for others. Administrators configure which absence types exist, from annual and special leave to parental leave, sabbatical, training, and working from home, each with its own color and rules. Sick notes are recorded as full day, morning, or afternoon, including child sick notes, and a note can later be converted into vacation when plans change. Overtime gets the same care: staff log hours and minutes for any period, choose to add or reduce their balance, and attach a comment for the record. Personal, department, and company calendars collect every absence, secret iCal links feed external calendar apps, and optional Google Calendar synchronization pushes new and changed entries. Email notifications for submissions, upcoming absences, substitute duties, and overtime entries can be switched on per person, and a token protected REST API exposes persons, absences, sick notes, and workdays. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache-2.0 licensed.