[kn100]

Interesting thought. I then wondered if perhaps we could introduce some kind of mechanism like a token that is authorized to spend a certain amount, and then wondered if we could take that concept to the extreme and have one key with some money loaded that users could put into websites. it was at this point I realised I'd just invented the credit card.

[Tiberium]

Such a service already exists - https://openrouter.ai. They're basically an aggregator of a lot of LLM models and APIs with unified billing (with both Stripe and crypto). And the main part related to your comment is that on OpenRouter you can create capped API keys with a specified limit in credits.

[__s]

Azure has SAS tokens which give time limited subpermission access derived from access key

https://learn.microsoft.com/en-us/azure/ai-services/document...

Used it to scope/isolate databases storing backups to a shared storage account

[reidjs]

Sounds more like a visa “gift” debit card

[TaylorAlexander]

Pretty cool that the inventor of the credit card is here on HN!

[addandsubtract]

Not to be that guy, but this would be an ideal use case for crypto.