The slot is arbitrated by the database
Two people confirming the same time in the same second is a race the database settles, not the interface. One of them books; the other is offered another time.
One workspace, eight modules
live — add-on, core in productionA booking page anyone can open without an account, backed by your real availability — not a form that emails you. And when the conversation happens on WhatsApp, the agent proposes times from that same calendar instead of asking you to check.
A public booking page: a day with four free times, one of them chosen, no account needed, and the reminders that follow.
Every line below is running in production today.
The real flow
Two people confirming the same time in the same second is a race the database settles, not the interface. One of them books; the other is offered another time.
Anyone can reach it, so it is treated as hostile input: anti-spam, rate limiting, and a booking that stays idempotent if the visitor hits the button twice.
The slot is checked again when the visitor confirms — not when the page was loaded. A calendar that offers a time it already gave away is worse than no calendar.
What is running today, and what is not:
Miira answers on WhatsApp and proposes the times Ciita has free — same platform, same calendar, no copy-paste in between.