This story gets file into the “way in future” bucket, because the infrastructure needed to make happen doesn't even exist. Beyond research from API grandfather John Musser (@johnmusser), and a few other blog posts or conference decks, there is no standardization of monetization strategies and pricing across APIs—making my idea impossible currently.
I won’t let that stop me! What I'd like to see is a developer credit system, that I can earn buy or earn credits for any single API, but I possess a credit account across all the APIs I depend on--as an API developer I want to buy credits for API usage, allowing me to buy in single, or bulk amounts, and apply against my regular API usage.
As an API provider, I could provide developers with an incentive using credits, trying to drive the behavior I'm looking to get from developers. With a credit system I could even pay developer's credits for doing common API ecosystem tasks like creating code libraries, generating how-to-guides, or even supporting other developers on the forum.
If there was a market for API credits, as a developer I could easily earn credits on one platform, and use them there, or possibly apply them to other platforms. I could also choose to just sell my credits on the open market to other API consumers, who might value the credits more than I do, or pay a rate that is lower than they'd get directly from a provider.
This is just a random thought I wanted to put out into the universe, that came up as I was evaluating the business models of some APIs I’m reviewing. We have a lot of work before something like this would be possible, but if someone stepped up to work on this problem across providers, I think there would be a pretty significant opportunity for them in coming years--think Amazon Web Service pricing, but across the board for the API space, applied to all business sectors. #huge