That is why for that use case it must be a channel between the user and the API provider, no peers in the middle of the payment. Maybe even a one-sided channel for simpler interactions and even less latency.

bitcoin

Lightning for API Micropayments?

note_bene

I've heard latency can be as low as milliseconds and a lot higher (20-30 seconds) in many cases. If a peer on the route goes offline in the middle of the payment, I suppose it could be stuck much longer - assuming peers don't roll it back on such failures.