Cal.com — Open-Source Scheduling Infrastructure

What it is

Cal.com is an open-source scheduling infrastructure platform that provides booking pages, calendar integrations, and scheduling APIs. It works as a self-hostable alternative to Calendly with features for teams, round-robin assignments, and webhook-driven workflows. The platform supports Google Calendar, Outlook, and CalDAV integrations.

It targets developers who want to embed scheduling into their applications, teams who need self-hosted scheduling for privacy, and businesses building appointment-based products.

How it saves time or tokens

Cal.com provides a complete scheduling backend via API. Instead of building calendar logic, time zone handling, conflict detection, and email notifications from scratch, you embed Cal.com and configure it. For AI applications, you can automate scheduling -- an AI agent can create booking links, check availability, and schedule meetings through the API without manual intervention.

How to use

1. Self-host with Docker:

git clone https://github.com/calcom/cal.com.git
cd cal.com
npm install
npx turbo dev

1. Or use Docker:

docker pull calcom/cal.com
docker run -p 3000:3000 calcom/cal.com

1. Embed in your application:

<!-- Embed a booking page -->
<iframe src="https://cal.com/your-username/30min" width="100%" height="700"></iframe>

<!-- Or use the JavaScript embed -->
<script>(function (C, A, L) { /* cal.com embed script */ })(window, 'https://cal.com', 'init');</script>

Example

// Use Cal.com API to create a booking programmatically
const response = await fetch('https://api.cal.com/v1/bookings', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        'Authorization': 'Bearer cal_your_api_key'
    },
    body: JSON.stringify({
        eventTypeId: 1,
        start: '2026-04-20T10:00:00Z',
        end: '2026-04-20T10:30:00Z',
        responses: {
            name: 'AI Agent Booking',
            email: 'user@example.com'
        }
    })
});

const booking = await response.json();
console.log('Booking created:', booking.uid);

Related on TokRepo

• AI tools for automation -- Workflow automation tools
• AI tools for self-hosted -- Self-hostable infrastructure

Common pitfalls

• Self-hosting requires PostgreSQL and proper email configuration for booking notifications. Without email, users will not receive confirmation emails.
• Time zone handling is complex. Ensure your integration sends UTC timestamps and lets Cal.com handle time zone conversion for the user.
• The API has rate limits. For high-volume booking scenarios, cache availability data and batch requests rather than querying per-user.