What Doodle did before ads and paywalls took over: Rallly (three L's) lets you propose a few dates, share a link, and watch an availability grid fill in - no email threads, no forced accounts, no "$6.95/month to remove ads." The availability grid makes the winning slot obvious at a glance, comments on each poll keep the "I can do Tuesday if we start late" discussion attached to the decision instead of buried in chat, and email notifications fire as votes and comments arrive. When consensus lands, finalize the winning option and everyone gets notified. The stack is modern TypeScript - Next.js, tRPC, Prisma over PostgreSQL, Tailwind - with a clean, genuinely mobile-friendly UI, dark mode, and community translations in 10+ languages. Self-hosting means unlimited polls and unlimited participants with meeting data on your server rather than a scheduling SaaS. It pairs naturally with Cal.com: Rallly answers "which time works for everyone?", Cal.com handles "book a slot on my calendar." AGPL-licensed.

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.

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.

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 binary replaces your booking link and your meeting room: Calnode is a complete scheduler you run yourself, small enough to audit and cheap enough to forget. Create event types with durations, custom questions, and locations, set DST-correct availability with date overrides, and share a booking page where guests pick a slot, reschedule, or cancel without an account. Two-way sync with Google Calendar, Microsoft 365, and CalDAV checks real free and busy time across every connected calendar, then mints Meet or Teams links automatically. Teams route bookings round-robin, collectively, or by priority, while paid event types collect through Stripe before the slot confirms. Choose Calnode Rooms and the meeting itself happens in the browser on your LiveKit server, with host controls, consent-aware recording into your own storage, and an AI notetaker that files a transcript and summary on the booking. Agents get first-class access through the REST API, HMAC-signed webhooks, and a native MCP server, and visitors can even book by describing a time in plain language. Everything runs from one static binary and one SQLite file with streaming Litestream backups. 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.

Share a link, and let people book time with you without the email volley that usually decides when a meeting happens. calrs connects to the calendar you already use, whether that is Nextcloud, Fastmail, BlueMind, iCloud, or any other CalDAV server, computes your real free and busy times from synced events and your availability rules, and shows guests only the slots that genuinely work. Create event types for intro calls, support sessions, or coaching, each with its own duration, buffers, minimum notice, booking limits, and confirmation mode, then publish them on your public profile or keep them private behind single-use invite links. Teams get round-robin scheduling that picks the least busy member, collective meetings that require everyone free, and dynamic group links that intersect several calendars on the fly for a one-off call. Guests pick a slot in their own timezone, receive HTML email with calendar invites attached, and can cancel or reschedule themselves from the confirmation email, while you approve pending bookings from the dashboard or straight from your inbox. When a slot looks wrong, the availability troubleshooter draws a timeline showing exactly which event or rule blocked it. Reminders go out before meetings, credentials are encrypted at rest, and the whole interface speaks ten languages with seven themes. 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.

One link replaces the scheduling dance: Thunderbird Appointment publishes your availability as a booking page where visitors choose a slot and the meeting lands on your calendar. You connect the calendars you already keep, Google Calendar or any CalDAV server, and the service reads your busy times and writes new bookings back as real events. Weekly schedules define the days and hours on offer, the length of each slot, and how far ahead or how last-minute a booking may be. Each booking page carries its own title, agenda, and location, from a street address to a Zoom link created for the meeting automatically. Visitors see open times in their own timezone, pick one, and leave their name and email; no account is required on their side. Requests can land as confirmed bookings right away or wait for your approval first, and every booking appears in your bookings list with attendee details. Your own calendar view gathers every connected calendar in one place, so personal and work commitments stop colliding. The interface speaks several languages, honors light and dark themes, and lets each user set the week start and 12 or 24 hour clocks. Self-hosters sign in with a password, and larger deployments can plug in an OIDC provider for single sign-on. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MPL-2.0 licensed.

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.

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.

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.

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.

SilentSuite is an end-to-end encrypted sync service for your calendar, contacts, and tasks, where the server stores only ciphertext and cannot read a single event, name, or plan. Encryption happens on your devices with keys derived locally, so record contents are sealed before upload and opened only on another trusted device of yours. Manage everything in the web app, sync a phone through the Android adapter's system calendar, contacts, and task providers, or connect desktop apps like Thunderbird and GNOME Calendar through the local Bridge. The Bridge speaks CalDAV and CardDAV only on localhost, then forwards encrypted records upstream, so standard desktop clients work without ever exposing plaintext to the server. Import and export keep exit paths open, and because sync rides the open Etebase protocol, your data model stays inspectable rather than locked into a proprietary format. Self-hosting unlocks every feature at no cost: one Compose file starts the sync server and PostgreSQL, with open registration you can close after your own account exists, nightly backup tooling, and Umbrel packaging. Signing up hosted users is not required at all; the same web app, Android adapter, and Bridge run against your own server with your domain. 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.

Small teams do not need another cloud subscription to know who is doing what this week: Work-Calendar runs your whole plan, do, finish, archive loop on one little server you own. The week view lays out every member's tasks across seven day columns with today highlighted, so standups start from the same picture instead of five private lists. Three kinds of tasks cover real work: project tasks, one-off tasks you can assign to yourself or teammates, and fixed recurring tasks on daily, weekday, monthly, or specific-date schedules. Anything unfinished carries over to the next day automatically, and completion records can be corrected by the assignee or sent back with a reason by the owner. Projects get spaces with folders, files up to 20MB, meetings with AI-generated minutes from pasted or dictated transcripts, timelines, and closing reports that an admin approves. Roles for superadmin, admin, and member, plus per-group rules, decide who may create projects directly, who needs approval, and who can use the built-in AI assistant, which drafts task and project changes as reviewable cards rather than acting silently. Inbox notifications, personal diaries, and daily statistics round out the routine, and keyboard shortcuts drive the whole interface. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

The family calendar nobody opens helps nobody, so DinkyDash puts it on a screen the household walks past. Paste in iCal links from Google, iCloud and Outlook calendars and the board merges them into one agenda in time order, big enough to read from across the kitchen, with tomorrow tucked underneath when the day leaves room. A personal calendar can share only the events marked for a partner and keep work and private appointments to itself. Chores answer the daily argument on their own: whose turn it is moves on with the date, so nobody ticks anything off. Birthdays, holidays and special dates count down in the corner, and once a day the board gets a fresh headline written about your actual day, with a useful note parked under the agenda. Light and dark themes come from the settings page, and that same settings page on your phone edits the configuration file directly, comments preserved. A preview page shows the board at Pi, TV and tablet sizes side by side before you mount anything. There is deliberately no login: it assumes your home network, rewards you with a board you never sign into, and asks to stay behind a VPN or an authenticated proxy if you view it away from home. 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 self-hosted site can publish your event calendar, sell tickets, take bookings, and send the newsletter. Event Schedule gives venues, performers, and curators their own schedule types, and a curator page gathers events from the venues and performers it follows. Recurring patterns cover daily, weekly, monthly-by-weekday, and yearly dates with per-date exceptions, and calendars import from ICS feeds, Google Calendar, or Eventbrite. Tickets come in several types with promo codes, waitlists, gift cards, and a drag-and-drop seating plan, and payments go through Stripe, PayPal, Payfast, Razorpay, or cash straight to your own accounts. Door staff scan QR tickets in a browser and a live dashboard counts arrivals. Appointment pages sync both ways with Google Calendar, Outlook, and CalDAV. The newsletter editor sends segmented, A/B tested campaigns through your own SMTP server, and optional AI features turn pasted text or flyer images into draft events. Analytics, an audit log, TOTP two-factor login, signed webhooks, a REST API, and twelve interface languages cover the admin side. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AAL licensed.