Stop double bookings across two calendars

The pattern is always the same. The booking system thinks Thursday at 2pm is free, because as far as it knows it is. Your own calendar has had a hospital appointment in that slot for three weeks. Neither is wrong. They have simply never been introduced.

This is worth fixing properly, because the failure is public: the client turns up, you are not there, and no explanation makes that a good experience.

The rule that prevents it

One calendar decides whether you are free. Everything else can display appointments, but only one source gets to answer the question "is this slot available".

In practice that means connecting the calendar you actually use — the one with your dentist appointment, your kid's sports day, the delivery slot — so that anything in it blocks the equivalent slot in your booking page. Not copying events across. Not remembering to block time manually. Connecting them, so it happens whether or not you remember.

Calendar sync in Bookify does this in both directions: your existing commitments block availability, and every new booking is written into the calendar you already check. Google Calendar and Apple/iCloud both work.

What "both directions" actually buys you

It is easy to underestimate the second half. Blocking availability from your calendar prevents the double booking. Writing bookings into your calendar is what keeps you from causing one.

If your appointments only exist inside the booking system, then when your partner asks what you are doing on Saturday you check the calendar on your phone, see nothing, and agree to something. The booking was real; it was just somewhere you do not look. Two-way sync means the answer is in the same place as the rest of your life.

The team version of the same problem

With more than one person, this multiplies. Each person has their own outside commitments, and no central diary can know about them unless each calendar is connected individually.

The important detail is that it should be per person: each team member connects their own calendar, and it affects only their own availability. Nobody needs to see anyone else's private events for this to work — the system only needs to know that a block of time is spoken for. Teams covers how each person's hours, services and calendar sit together.

Where it matters most

Anywhere the appointment is long and the person is specific. Physiotherapy and massage both book a named practitioner for a substantial block, so a clash costs a whole slot and a rebooking call. Clinics and dentists have the same shape with a longer waiting list behind it. Photographers feel it most sharply of all, because the clash may only surface on the day, when both parties have already travelled.

Trades where anyone can serve anyone — a walk-in barbershop, say — feel this less, because a clash can be absorbed by whoever is free.

What to check when a clash happens anyway

If one still slips through, it is almost always one of three things, in this order:

1. A calendar that was never connected, or was connected and later revoked — a changed password or a removed app permission will silently stop the sync.
2. An event marked "free" rather than "busy". Most calendars let you mark an event as not blocking, and holiday or birthday calendars often default that way. Only busy events block.
3. A missing buffer, which is not really a double booking — it is two appointments that are legitimately adjacent with no room to clean down between them. That is a working hours setting, not a sync problem.

The unglamorous conclusion

There is no clever scheduling algorithm that fixes this. The fix is boring: connect the calendar you actually use, check that new bookings appear in it, and make sure everyone on the team has done the same. Ten minutes each, once — and then the question of whether you are free has exactly one answer.

If you are still setting things up, moving from DMs and a paper diary covers the order to do it in.