Automate Booking Follow-Ups with Cal.com and Make

You can automate booking follow-ups by sending every Cal.com event (new booking, reschedule, cancellation and meeting ended) to a single Make webhook, then using a router to send the right email and log each event in Google Sheets. Cal.com already sends confirmations and reminders. This scenario covers what it doesn't: a question before the call, a rebooking link when someone cancels, a thank-you after the meeting, and a log of everything that happened.

I built and tested it for a fictional small business, Brightside Cleaning Co., on the free plans of Cal.com and Make. All four routes ran with real bookings, and the test surfaced five problems worth knowing before you build your own. They are in the "What I learned" section.

Disclosure: the Make and Cal.com links on this page are affiliate links. If you sign up through them, Biz Flow Craft may earn a commission at no extra cost to you. It doesn't change what we recommend.

What you'll build

Each event becomes a new row, so the sheet keeps the full history of every booking instead of overwriting it.

Before you start

• A Cal.com account. The free plan is enough: one user, unlimited event types and webhooks. Create one here (affiliate link; new users get 20% off paid plans for 12 months).
• A Make account. The free plan includes 1,000 credits a month. Sign up here (affiliate link).
• An event type that uses Cal Video as the location. The "meeting ended" event only fires for meetings held on Cal Video.
• A Google Sheet called "Booking Log", with a tab named Bookings and these headers in row 1: received_at, event, booking_uid, name, email, start_time, event_type.

Why one webhook instead of the Cal.com app

Make has a Cal.com app, and its triggers are instant. But each event is a separate trigger: Watch Booking Created, Watch Booking Rescheduled, Watch Booking Cancelled and Watch Meeting Ended. In Make, a scenario has only one trigger, so the app approach means four scenarios. The free plan allows two active scenarios.

A Make custom webhook receives all four events in one scenario. Cal.com tells you which event it is in a field called triggerEvent, and a router does the rest.

Step by step

1. Create the webhook in Make

   Create a scenario, add Webhooks → Custom webhook, click Add and name it Cal.com bookings. Leave API key authentication empty: Cal.com can't send that header, and Make would reject its requests. Copy the webhook address. Treat it like a password: anyone with it can send data to your scenario.

2. Point Cal.com to it

   In Cal.com, go to Settings → Developer → Webhooks → New and paste the address as the subscriber URL. Cal.com selects every event by default, and each one would run your scenario and use credits. Click Clear all triggers and add only Booking created, Booking rescheduled, Booking cancelled and Meeting ended.

   

3. Capture a sample booking

   Click Run once in Make and book a test meeting on your public page. The webhook learns the data structure. The client's details are inside payload → attendees[1]: name, firstName, email and timeZone.

   

4. Block duplicates

   Right after the webhook, add Google Sheets → Search Rows on the Bookings tab, with two conditions: event equal to {{1.triggerEvent}} AND booking_uid equal to {{ifempty(1.payload.uid; 1.uid)}}. Set the limit to 1. Then add a filter on the next link: Total number of bundles, Numeric operators: Equal to 0. If the event is already in the sheet, the scenario stops there.

5. Add the router and four routes

   Add a Router with four routes. Each route gets a filter on {{1.triggerEvent}} (Text operators: Equal to), a Gmail → Send an email module with Body type set to Raw HTML, and a Google Sheets → Add a row module.

   

6. Write the emails

   Show the meeting time in the client's own time zone with formatDate. The emails below are the ones I tested.

   

7. Log every event

   Map the same seven columns in each Add a row module (the table is further down). Set the scenario to Active. Because the trigger is instant, it only runs, and only uses credits, when Cal.com sends an event.

   

The four emails

Booked (filter: BOOKING_CREATED). Subject: You're booked, {{1.payload.attendees[1].firstName}}

Hi {{1.payload.attendees[1].firstName}},<br><br>
Thanks for booking a call with us. See you on <b>{{formatDate(1.payload.startTime; dddd, MMMM D [at] h:mm A; 1.payload.attendees[1].timeZone)}}</b>.<br><br>
To make the most of it, reply to this email with one thing you'd like to cover.<br><br>
Thanks,<br>The Brightside team

Rescheduled (filter: BOOKING_RESCHEDULED). Subject: Your call has a new time

Hi {{1.payload.attendees[1].firstName}},<br><br>
Your call has been moved to <b>{{formatDate(1.payload.startTime; dddd, MMMM D [at] h:mm A; 1.payload.attendees[1].timeZone)}}</b>. No need to do anything else.<br><br>
Thanks,<br>The Brightside team

Cancelled (filter: BOOKING_CANCELLED). Subject: Your call was cancelled

Hi {{1.payload.attendees[1].firstName}},<br><br>
Your call has been cancelled. If you'd like to pick a new time, you can <a href="YOUR-BOOKING-PAGE">book here</a>.<br><br>
Thanks,<br>The Brightside team

Follow-up (filter: MEETING_ENDED). Subject: Thanks for your time today. This event uses different field paths; see "What I learned".

Hi {{first(split(1.attendees[1].name; space))}},<br><br>
Thanks for the call today. If you have any questions, just reply to this email.<br><br>
Thanks,<br>The Brightside team

The booking log

Replace America/Sao_Paulo with your own time zone.

Testing it

I tested every route with a client email alias (yourname+client@gmail.com), so all messages reached my inbox:

1. Booked a meeting on the public page: welcome email and a BOOKING_CREATED row.
2. Clicked Reschedule in Cal.com's confirmation email: "Your call has a new time" and a BOOKING_RESCHEDULED row.
3. Clicked Cancel in the new confirmation email: the rebooking email and a BOOKING_CANCELLED row.
4. Joined and left the Cal Video call: "Thanks for your time today" and a MEETING_ENDED row.
5. Replayed the same event in Make: it stopped at the duplicate filter, with no second email.

What it costs

Cal.com's free plan covers one person with unlimited event types. In Make, each event uses about four credits: the webhook, the duplicate search, the email and the sheet row. A booking that is rescheduled once and then held uses about 12 credits. On the free plan's 1,000 credits, that's roughly 80 bookings a month with full follow-up. Make's Core plan starts at $9 a month billed yearly for 10,000 credits. Instant webhooks only use credits when something happens, so there's no cost for idle time.

To check whether that's worth it for your volume, try the automation ROI calculator.

What I learned building it

1. The Cal.com app has four separate triggers. Using it means four scenarios. A custom webhook handles all events in one scenario, which matters on a plan with two active scenarios.
2. Rescheduling creates a new booking ID. Cal.com cancels the old booking and creates a new one. If you update rows by ID instead of adding them, the rescheduled booking won't match the original.
3. "Meeting ended" uses a different format. The other events put the data inside payload. MEETING_ENDED puts it at the top level, and the attendee has name but no firstName. Mapping it like the other routes gives empty emails and an error in Gmail.
4. Cal.com can send the same event twice. Without the duplicate check, one reschedule produced two identical rows and would have sent two emails.
5. An empty search still passes a bundle. When Search Rows finds nothing, Make still passes one bundle with Total number of bundles = 0. Filter on that field directly. Adding an aggregator to count results gave 1 instead of 0 and blocked every event.

Common errors

Looking for more scenarios like this one? See automating client onboarding with Make and automating customer support emails. If you're still choosing a platform, read Zapier vs Make vs n8n.

FAQ

Does Cal.com already send booking confirmations?

Yes. Cal.com sends confirmations, reminders and cancellation notices. This scenario adds what it doesn't send: a question before the call, a rebooking link on cancellation, a follow-up after the meeting and a log of every event.

Can I do this with Calendly instead of Cal.com?

Yes, with a webhook or Calendly's Make app. The event names and field paths are different, so you'd need to remap the router filters and the email fields.

Why does the follow-up need Cal Video?

Cal.com only knows a meeting has ended when it hosts the call. For Zoom or Google Meet meetings, schedule the follow-up from the booking end time instead.

How many bookings does the free Make plan handle?

Each event uses about four credits. With one reschedule per booking on average, 1,000 free credits cover roughly 80 bookings a month with full follow-up.