The awkward moment it prevents
Two customers arrive for the same appointment. One goes home disappointed, and probably does not book again. It is the one thing a booking system must never do, and CaliDiary is built so it cannot: every booking, from every route in, is checked inside a lock before it is saved. It is part of every plan, including the free plan.
The problem it solves
A booking page shows free times. Between the moment a visitor sees a time and the moment they press Book, someone else may take it: another visitor, a colleague adding a phone booking, or a customer moving their appointment. Simple booking systems check once, when the page loads, and save without checking again. That is how double bookings happen, and they are usually found out when two customers arrive at once.
How CaliDiary prevents it
- Free times are worked out fresh. When the booking form opens, it asks your website which times are free right now, taking in opening hours, breaks, time off, special dates, buffers before and after, minimum notice and existing bookings.
- Every booking is saved inside a lock. When someone presses Book, CaliDiary takes a database lock, checks the time again against everything already booked, and only then saves. A second booking for the same person and time has to wait for the lock, and then finds the time taken.
- The second visitor is looked after. They see "Sorry, that time has just been taken", the calendar reloads with times that are really free, and their answers stay filled in.
The same check runs for every way a booking can be made or changed: the booking form, staff adding a booking, and moving an existing booking to a new time.
Groups, requests and teams
- Group sessions: the lock counts places as well as times, so the last place goes to exactly one person. See group sessions.
- Your own calendar: on Solo and Pro, two-way calendar sync treats private appointments in Google, Outlook or Apple calendars as busy, so they are never double-booked either.
- Requests you approve: a request holds its time while it waits for you, so nobody else can take it. If you decline, the time is free again. Unanswered requests are declined automatically when the appointment would have started.
- Teams: with "anyone" chosen, CaliDiary gives the booking to the least busy person who is free, and the lock applies to that person's diary.
- Buffers: preparation and tidy-up time around appointments is protected in the same way, so a booking can't squeeze into a buffer.
Summer time and time zones
Opening hours are kept as your local clock times, and bookings and time off are stored in UTC, so a diary stays right when the clocks change. When the clocks go forward, CaliDiary never offers a time that does not exist that night.
Paying online
With online card payments (Solo and Pro), a paid booking holds its time for 15 minutes while the visitor pays, so nobody else can take it in the middle of checkout.
