Can You Schedule a WhatsApp API Message?

Why Meta does not schedule for you

The API is a transport. It accepts a message and delivers it, and deliberately holds no state about your intentions. Everything to do with when and whether to send belongs to the system making the call.

That is fine, but it means scheduling quality varies enormously between platforms, and it is worth asking how yours behaves when something goes wrong.

The parts that actually bite

Timezones first. Store what the person meant, which is a local time and a place, rather than only the instant you computed. Otherwise a send scheduled before a daylight-saving change fires an hour out.

Then lateness. If a worker was down and a job is three hours overdue, should it still go? For a reminder about an event that has now started, almost certainly not. A scheduler without a staleness rule will cheerfully send yesterday reminders.

Finally the window. A free-form message scheduled for tomorrow may be illegal by the time it runs, because the customer last messaged you today. Use a template for anything scheduled more than a few hours out.