How to Connect InstantDM with Cal.com (Step-by-Step Guide)

Cal.com is an open-source scheduling platform - like Calendly, but self-hostable and free. Connecting InstantDM to Cal.com lets you send booking links in Instagram DMs and track when leads schedule appointments.

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Why Use Cal.com with InstantDM?

• Free and open source - no per-seat pricing
• Self-hostable - full control over your data
• Webhooks included - booking notifications on all plans (unlike Calendly)
• API access - programmatic control over events and bookings
• Custom branding - white-label the booking page

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What You'll Need

Requirement	Details
InstantDM account	Trendsetter, Trendsetter Pro, or any Multi plan
Cal.com account	Free (cal.com) or self-hosted
InstantDM API key	Found at Settings → API in your InstantDM dashboard

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Sending Booking Links in DMs

Get Your Cal.com Link

Your booking link is https://cal.com/yourname/30min (or your custom domain if self-hosted).

Add to InstantDM Flow

Send as a button in your DM flow:

{
  "action": "send_message",
  "type": "buttons",
  "recipient_id": "INSTAGRAM_USER_ID",
  "message": "Let's schedule a call! Pick a time:",
  "buttons": [
    { "title": "Book a Call", "url": "https://cal.com/yourname/30min" }
  ]
}

Pre-Fill with Lead Data

https://cal.com/yourname/30min?name=John+Doe&email=john@example.com

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Booking Notifications via Webhooks

Cal.com includes webhooks on all plans (including free).

Step 1: Create a Webhook in Cal.com

1. Go to Settings → Developer → Webhooks.
2. Click New Webhook.
3. Set the URL to your server.
4. Select trigger: Booking Created.
5. Save.

Step 2: Handle the Webhook

const express = require('express');
const app = express();
app.use(express.json());

app.post('/calcom-webhook', async (req, res) => {
  const { triggerEvent, payload } = req.body;
  
  if (triggerEvent !== 'BOOKING_CREATED') {
    return res.status(200).json({ status: 'skipped' });
  }
  
  const attendeeEmail = payload.attendees?.[0]?.email;
  const startTime = payload.startTime;
  
  // Look up Instagram user by email
  const instagramUserId = await lookupInstagramUser(attendeeEmail);
  
  if (instagramUserId) {
    await fetch('https://api.instantdm.com/api-webhook', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${process.env.INSTANTDM_API_KEY}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        action: 'send_message',
        type: 'text',
        recipient_id: instagramUserId,
        message: `✅ Call booked for ${new Date(startTime).toLocaleString()}! See you then.`,
      }),
    });
  }
  
  res.status(200).json({ status: 'processed' });
});

app.listen(3000);

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Via Make.com

1. Use a Custom Webhook trigger in Make.com to receive Cal.com booking events.
2. Add an HTTP Request module to send a confirmation DM via InstantDM API.

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Troubleshooting

Issue	Solution
Webhook not firing	Verify the webhook URL is publicly accessible. Check Cal.com webhook settings.
Pre-fill not working	Ensure query parameters are URL-encoded.
Can't match booking to Instagram lead	Store email-to-Instagram mapping when leads are captured.

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Cal.com vs. Calendly

Feature	Cal.com	Calendly
Price	Free (self-hosted) or free tier	Free tier, Pro from $10/mo
Webhooks	All plans	Professional+ only
Self-hosting	Yes	No
API access	All plans	Professional+
Open source	Yes	No

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What's Next

• Set up Calendly if you prefer a managed solution.
• Connect to Google Calendar for direct calendar integration.
• Read the Slack guide for booking notifications in Slack.
• Explore the full API docs at instantdm.com/instagram-api-docs.