AWS is arguably an API, and I shovel a ton of money their way. Stripe is another one, though that ends with me getting paid, so I guess that technically doesn't count unless I start losing money using it. There's also the APIs backing all the apps I pay for, since I don't talk to them via a webpage. But then, if we look at every web page that hits an API to get a list of items to display, instead of that list coming over on the html itself, that'd be an API, technically. ChatGPT is an API I hit a bunch via non-web browser clients that I pay for.