Micropayments with Lightning is an extremely exciting use case. But I haven't seen any actual uses, or libraries for this yet.
The closest* I've seen is right here on StackerNews and the occasional podcast or blog that uses an LN invoice for access to the material.
So does anyone have
  • links to an API that uses Lightning for access per request?
  • Or links to a dev project building this?
*: SN doesn't truly qualify as micropayments in my mind because it uses a hosted custodial wallet that is making payments to/from other users' hosted custodial wallet. I call this the "gift card" model because you need to manually load/unload funds from it. Looking for the client sending a request to the api to provide a payment on a one-off, no registration or manual steps required.
Also interested in any discussion around:
  • the estimated latency such a system would introduce and workarounds
  • business models, especially around content and/or software tools, where a network of LN actors would share earnings on user payments.
have you looked at LSATs at all? basically your client hits an API endpoint, it returns an HTTP 402 Payment Required with a lightning invoice, you pay it and now have access to the resource.
Is that the sort of thing you're thinking of?
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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.
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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.
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