Cal.com
Overview
Cal.com is an open-source scheduling platform and one of the most popular alternatives to Calendly. It lets individuals, teams, and businesses create shareable booking pages (cal.com/yourname) so people can book meetings, calls, and appointments without email back-and-forth. The core application is fully open source and self-hostable: the GitHub repository now lives under the name Cal.diy, the community edition of Cal.com, licensed MIT, while the commercial hosted product continues at cal.com. Built with TypeScript, Next.js, tRPC, and PostgreSQL, it connects to Google, Outlook, Apple, and CalDAV calendars with two-way sync to prevent double bookings, and it works anywhere through an embeddable booking widget and a modern REST API.
Key Features
- Shareable booking pages: Short custom booking links with configurable event types, recurring and seated events, and private hashed links.
- Availability control: Availability schedules, date overrides, buffer times, minimum notice, daily/weekly booking limits, and out-of-office settings.
- Calendar and video integrations: Two-way sync with Google, Outlook/Office 365, Apple, CalDAV, Zoho, and Exchange calendars; meetings via Cal Video, Zoom, Google Meet, Microsoft Teams, and Jitsi.
- Payments: Collect Stripe or PayPal payments on booked events, with configurable currency and fee handling.
- Developer platform: REST API v2, API keys, OAuth clients, embed (inline, popup, floating button), webhooks, and integrations with Zapier, n8n, Make, CRMs, and messaging tools.
- Multilingual: The booking experience is available in 65+ languages.
Why Use It
Cal.com is the leading open-source answer to Calendly. The hosted product is free for individuals, while the MIT-licensed Cal.diy community edition can be self-hosted with Docker for full data control and privacy. Developers value the clean embeddable widget and REST API v2 for building scheduling into their own products, and the project has one of the largest communities in the category (roughly 48,000 GitHub stars).
Use Cases
- Freelancers and consultants: Share a booking page in proposals or bios so clients can grab a slot without email ping-pong.
- Sales and support teams: Route leads and customers to availability, collect payment for paid sessions, and reduce no-shows with automated reminders.
- Developers: Embed scheduling directly into SaaS products with API v2 or embed links, or self-host the community edition for full control.
- Education and telehealth: Academic advising, tutoring, and patient appointments with calendar sync and rescheduling notices.
Alternatives
- Calendly — The popular proprietary scheduling SaaS that Cal.com positions itself against; easy to set up but closed source and less customizable.
- Easy!Appointments — Self-hosted, open-source (GPLv3) appointment scheduling web app aimed at service businesses.
- Rallly — Open-source, self-hosted tool for scheduling group meetings via polls, ideal for finding a time with many participants.
- Nextcloud — Self-hosted collaboration suite whose Calendar app includes appointment booking, alongside files, contacts, and tasks.
- Radicale — Lightweight self-hosted CalDAV/CardDAV server that can act as the calendar backend for a Cal.com instance.
Platform
Web application; self-hostable on Linux with Docker or via deploy guides for AWS, Azure, GCP, Railway, Render, and Vercel. Free iOS and Android apps and desktop apps for macOS, Windows, and Linux.
Licence
MIT License for the open-source community edition (published as Cal.diy). Commercial SaaS features such as teams, routing forms, workflows, and SAML SSO are managed by Cal.com, Inc.