What Halgo connects to

An integration earns its place when it removes a place you have to type something twice. That is a narrower test than it sounds, and most integrations fail it: they add a connection, a permission screen and a thing that can break, in exchange for a convenience you would not have missed.

For a private tutor there are really two joins that pass. The calendar, because the week already lives in one and a second copy of it is a guarantee that one of them will be wrong. And the call, because a lesson link that has to be found and pasted before every lesson is a small tax charged weekly, forever.

One-way sync is worse than none. A calendar that receives lessons but does not send changes back teaches you to distrust it within a month: you move something on your phone, it reappears, and from then on you check both. Two-way is the only version that lets you stop looking.

It also has to survive the ordinary mess — a lesson moved twice, a cancellation that keeps its credit, a booking made from the other device while you were offline. Those are the cases that decide whether a sync is usable, not the first happy import.

There is no accounting integration, because a tutor's books are small enough that exporting once a quarter beats a permanent connection to a ledger. There is no marketing or mailing-list integration: Halgo is not a place to build an audience from, and student contact details are the one category of data that should leave as rarely as possible.

Payments sit in the same category for now. Recording what a family has paid is a different problem from taking the payment, and the recording is the half that goes wrong — see students and billing.