Terminal.skills
Skills/cal-com
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cal-com

Expert guidance for Cal.com, the open-source scheduling platform for building booking and appointment systems. Helps developers integrate Cal.com's embed widgets, REST API, and webhooks to add scheduling capabilities to their applications.

#scheduling#calendar#booking#appointments#api
terminal-skillsv1.0.0
Works with:claude-codeopenai-codexgemini-clicursor
Source

Usage

$
✓ Installed cal-com v1.0.0

Getting Started

  1. Install the skill using the command above
  2. Open your AI coding agent (Claude Code, Codex, Gemini CLI, or Cursor)
  3. Reference the skill in your prompt
  4. The AI will use the skill's capabilities automatically

Example Prompts

  • "Review the open pull requests and summarize what needs attention"
  • "Generate a changelog from the last 20 commits on the main branch"

Documentation

Overview

Cal.com, the open-source scheduling platform for building booking and appointment systems. Helps developers integrate Cal.com's embed widgets, REST API, and webhooks to add scheduling capabilities to their applications.

Instructions

Embed Widget

Add a booking widget to any website:

tsx
// src/components/BookingWidget.tsx — Embed Cal.com scheduling in a React app
import Cal, { getCalApi } from "@calcom/embed-react";
import { useEffect } from "react";

export function BookingWidget() {
  useEffect(() => {
    (async () => {
      const cal = await getCalApi();
      // Configure the embed appearance
      cal("ui", {
        theme: "light",
        styles: { branding: { brandColor: "#6366f1" } },
        hideEventTypeDetails: false,
        layout: "month_view",       // "month_view" | "week_view" | "column_view"
      });
    })();
  }, []);

  return (
    <Cal
      calLink="your-team/discovery-call"   // Your Cal.com event link
      style={{ width: "100%", height: "100%", overflow: "scroll" }}
      config={{
        layout: "month_view",
        name: "Customer Name",              // Pre-fill guest name
        email: "customer@example.com",      // Pre-fill guest email
        notes: "Interested in Enterprise plan",
      }}
    />
  );
}

// Floating button that opens calendar in a popup
export function BookingButton() {
  useEffect(() => {
    (async () => {
      const cal = await getCalApi();
      cal("floatingButton", {
        calLink: "your-team/discovery-call",
        buttonText: "Book a Demo",
        buttonColor: "#6366f1",
        buttonTextColor: "#ffffff",
        buttonPosition: "bottom-right",
      });
    })();
  }, []);

  return null;   // The floating button renders itself
}

REST API Integration

Manage bookings, event types, and availability programmatically:

typescript
// src/cal/client.ts — Cal.com API client for server-side operations
const CAL_API_URL = "https://api.cal.com/v2";
const CAL_API_KEY = process.env.CAL_API_KEY!;

async function calFetch(path: string, options?: RequestInit) {
  const response = await fetch(`${CAL_API_URL}${path}`, {
    ...options,
    headers: {
      "Content-Type": "application/json",
      "cal-api-version": "2024-08-13",       // Pin API version for stability
      Authorization: `Bearer ${CAL_API_KEY}`,
      ...options?.headers,
    },
  });
  if (!response.ok) {
    const error = await response.json();
    throw new Error(`Cal.com API error: ${error.message}`);
  }
  return response.json();
}

// Create a new event type (e.g., "30-min Discovery Call")
async function createEventType(params: {
  title: string;
  slug: string;
  lengthInMinutes: number;
  description?: string;
  locations?: { type: string; link?: string }[];
}) {
  return calFetch("/event-types", {
    method: "POST",
    body: JSON.stringify({
      title: params.title,
      slug: params.slug,
      lengthInMinutes: params.lengthInMinutes,
      description: params.description,
      locations: params.locations ?? [
        { type: "integrations:google:meet" },  // Default: Google Meet
      ],
      bookingFields: [
        { name: "company", type: "text", label: "Company Name", required: true },
        { name: "teamSize", type: "select", label: "Team Size",
          options: ["1-10", "11-50", "51-200", "200+"], required: true },
      ],
    }),
  });
}

// Get available time slots for a date range
async function getAvailability(params: {
  eventTypeId: number;
  startTime: string;   // ISO 8601
  endTime: string;
  timeZone: string;
}) {
  const query = new URLSearchParams({
    eventTypeId: String(params.eventTypeId),
    startTime: params.startTime,
    endTime: params.endTime,
    timeZone: params.timeZone,
  });
  return calFetch(`/slots?${query}`);
}

// Create a booking
async function createBooking(params: {
  eventTypeId: number;
  start: string;         // ISO 8601 datetime
  attendee: { name: string; email: string; timeZone: string };
  metadata?: Record<string, string>;
}) {
  return calFetch("/bookings", {
    method: "POST",
    body: JSON.stringify({
      eventTypeId: params.eventTypeId,
      start: params.start,
      attendee: params.attendee,
      metadata: params.metadata,
      language: "en",
    }),
  });
}

// Cancel a booking
async function cancelBooking(bookingUid: string, reason?: string) {
  return calFetch(`/bookings/${bookingUid}/cancel`, {
    method: "POST",
    body: JSON.stringify({ reason }),
  });
}

// Reschedule a booking
async function rescheduleBooking(bookingUid: string, newStart: string) {
  return calFetch(`/bookings/${bookingUid}/reschedule`, {
    method: "POST",
    body: JSON.stringify({ start: newStart }),
  });
}

Webhooks

React to booking events in real time:

typescript
// app/api/cal-webhook/route.ts — Handle Cal.com webhook events
import { NextRequest, NextResponse } from "next/server";
import crypto from "crypto";

const WEBHOOK_SECRET = process.env.CAL_WEBHOOK_SECRET!;

// Verify the webhook signature to ensure it's from Cal.com
function verifySignature(payload: string, signature: string): boolean {
  const expected = crypto
    .createHmac("sha256", WEBHOOK_SECRET)
    .update(payload)
    .digest("hex");
  return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected));
}

export async function POST(request: NextRequest) {
  const payload = await request.text();
  const signature = request.headers.get("x-cal-signature-256") ?? "";

  if (!verifySignature(payload, signature)) {
    return NextResponse.json({ error: "Invalid signature" }, { status: 401 });
  }

  const event = JSON.parse(payload);

  switch (event.triggerEvent) {
    case "BOOKING_CREATED":
      // New booking — send confirmation, update CRM, notify sales
      await handleNewBooking({
        bookingId: event.payload.bookingId,
        attendeeName: event.payload.attendees[0]?.name,
        attendeeEmail: event.payload.attendees[0]?.email,
        startTime: event.payload.startTime,
        eventType: event.payload.eventTitle,
        metadata: event.payload.metadata,
      });
      break;

    case "BOOKING_CANCELLED":
      // Booking cancelled — update CRM, free up resources
      await handleCancellation({
        bookingId: event.payload.bookingId,
        reason: event.payload.cancellationReason,
      });
      break;

    case "BOOKING_RESCHEDULED":
      // Booking moved — update calendar integrations
      await handleReschedule({
        bookingId: event.payload.bookingId,
        oldTime: event.payload.previousStartTime,
        newTime: event.payload.startTime,
      });
      break;

    case "MEETING_ENDED":
      // Meeting finished — trigger follow-up sequence
      await triggerFollowUp(event.payload.bookingId);
      break;
  }

  return NextResponse.json({ received: true });
}

async function handleNewBooking(booking: any) {
  // Example: Create a deal in your CRM
  await crm.createDeal({
    name: `Demo: ${booking.attendeeName}`,
    contact: booking.attendeeEmail,
    stage: "discovery",
    source: "website-booking",
    metadata: booking.metadata,
  });

  // Notify the sales team via Slack
  await slack.postMessage({
    channel: "#sales-notifications",
    text: `📅 New ${booking.eventType} booked!\n👤 ${booking.attendeeName} (${booking.attendeeEmail})\n🕐 ${new Date(booking.startTime).toLocaleString()}`,
  });
}

Managing Team Availability

Configure round-robin scheduling and team calendars:

typescript
// src/cal/team-setup.ts — Configure team scheduling rules
async function setupTeamScheduling() {
  // Create a team event type with round-robin assignment
  const eventType = await calFetch("/event-types", {
    method: "POST",
    body: JSON.stringify({
      title: "Product Demo",
      slug: "product-demo",
      lengthInMinutes: 45,
      schedulingType: "ROUND_ROBIN",     // Rotate among team members
      hosts: [
        { userId: 101, isFixed: false },  // Participates in rotation
        { userId: 102, isFixed: false },
        { userId: 103, isFixed: true },   // Always included (e.g., sales engineer)
      ],
      beforeEventBuffer: 15,              // 15-min buffer before meetings
      afterEventBuffer: 10,               // 10-min buffer after
      minimumBookingNotice: 120,          // Minimum 2 hours notice
      slotInterval: 15,                   // Show slots every 15 minutes
      locations: [
        { type: "integrations:zoom" },    // Auto-create Zoom meeting
      ],
    }),
  });

  // Set working hours for the team
  await calFetch("/schedules", {
    method: "POST",
    body: JSON.stringify({
      name: "Business Hours",
      timeZone: "America/New_York",
      isDefault: true,
      availability: [
        // Monday-Friday 9 AM to 5 PM
        { days: [1, 2, 3, 4, 5], startTime: "09:00", endTime: "17:00" },
      ],
      // Block specific dates (holidays, company events)
      dateOverrides: [
        { date: "2026-12-25", startTime: null, endTime: null },  // Christmas — unavailable
        { date: "2026-12-31", startTime: "09:00", endTime: "12:00" },  // NYE — morning only
      ],
    }),
  });
}

Installation

bash
# React embed
npm install @calcom/embed-react

# For self-hosted Cal.com (Docker)
git clone https://github.com/calcom/cal.com.git
cd cal.com
cp .env.example .env
docker compose up -d

Examples

Example 1: Setting up Cal Com with a custom configuration

User request:

I just installed Cal Com. Help me configure it for my TypeScript + React workflow with my preferred keybindings.

The agent creates the configuration file with TypeScript-aware settings, configures relevant plugins/extensions for React development, sets up keyboard shortcuts matching the user's preferences, and verifies the setup works correctly.

Example 2: Extending Cal Com with custom functionality

User request:

I want to add a custom rest api integration to Cal Com. How do I build one?

The agent scaffolds the extension/plugin project, implements the core functionality following Cal Com's API patterns, adds configuration options, and provides testing instructions to verify it works end-to-end.

Guidelines

  1. Use embed for public booking — The React embed handles time zones, availability, and confirmations automatically
  2. Pin API versions — Include cal-api-version header to avoid breaking changes when Cal.com updates
  3. Verify webhook signatures — Always validate x-cal-signature-256 to prevent spoofed events
  4. Buffer time between meetings — Set beforeEventBuffer and afterEventBuffer to prevent back-to-back meetings
  5. Pre-fill known data — Pass name, email, and context via embed config to reduce friction for returning users
  6. Use metadata for attribution — Pass UTM params, plan interest, or referral codes through booking metadata
  7. Handle all webhook events — Don't just handle BOOKING_CREATED; cancellations and reschedules need cleanup too
  8. Self-host for compliance — If you need data residency (GDPR, HIPAA), self-host Cal.com with Docker

Information

Version
1.0.0
Author
terminal-skills
Category
Development
License
Apache-2.0