MultiReserva puts rooms, courts, studios and professionals' schedules on one board everyone can see. Double bookings are blocked by the database itself, not by someone remembering to check. Share a public link so people can request a time without an account, approve with one click, and the notice goes out by email or WhatsApp. Built for churches, schools, clinics, coworkings and salons. Free plan forever; paid plans from US$29/month.