---
title: "Appointment booking with calendar invites, built by Claude Code on Elements"
author: "@chris"
author_url: https://elements.dev/u/@chris
published: 2026-09-30T20:38:33.745Z
url: https://elements.dev/demos/appointment-booking-with-calendar-invites-built-by-claude-99jsw1df
kind: post
format: article
---

# Appointment booking with calendar invites, built by Claude Code on Elements

by [@chris](https://elements.dev/u/@chris) · 2026-09-30

## Description

Meeting types, weekly hours and date overrides, booking pages shown in each guest's own time zone, and emailed calendar invites with reminders, reschedule and cancel.

Slotnook needed open slots computed from weekly hours and overrides, booking pages that update while a guest is looking, emailed calendar invites, and reminders on a schedule. Each of those is a part of Elements, so the agent spent its 21 minutes on the scheduling itself.

- **Booking pages that update live.** A channel tells every open booking page when a host's calendar changes, so a time another guest just took drops out of the picker on the spot.
- **Booking as a function call.** The booking page calls `@rpc` functions to read open times, book, reschedule and cancel, with types checked from the page to the database. Booking locks the host inside a transaction, so each time goes to exactly one guest.
- **Open times from SQL.** A migration defines meeting types, weekly hours, date overrides and bookings, plus a SQL function that turns them into open start times with buffers. A second migration seeds two consultants in Los Angeles and Berlin with five meeting types and bookings from guests in their own time zones.
- **Invites by email.** Each confirmation, reschedule and cancellation is a background job that sends an email with a calendar file attached, so the guest's calendar follows every change.
- **Reminders on a schedule.** One cron line runs a job every five minutes that sends a reminder for each booking starting within a day.
- **Sessions.** Hosts sign in to manage their meeting types, hours and bookings, and every host action checks that the booking belongs to the signed-in user.