1. Cal.diyBooking page or embed on this site. Holds services, barbers, hours, availability.
    2. WebhookBOOKING_CREATED / BOOKING_CANCELLED / BOOKING_RESCHEDULED → reminder worker.
    3. Reminder workerSmall server with a 5-minute cron. Sends the confirmation and the 1-hour reminder.
    4. SMS / WhatsApp providerNetgsm, İleti Merkezi, Twilio or the WhatsApp Business API.
    5. Confirm link or reply"Coming" marks it confirmed. "Can't make it" cancels it through the Cal.diy API and the slot reopens.

    Real in this demo: the booking flow, availability, the calendar file, this dashboard. Simulated: sending messages and the server job.