I'm gonna put a different tone to this discussion because I get a little angry about this. Pay for an API key? I don't think that's fair. You state that we get a lot of utility out of the API but that's not true. We do not get more utility then other, free users have. If we want to util that source, we have to make those utilities our selves. That's not for free: we have to invest time and effort to make them. What you try to do here is make money out of our own utilities that can exist without your API. Your benefit of an API is that we use a less resource intensive way. Our benefit is that it is a little easier to code something around that. So it is WIN/WIN. But the greed... To be honest: I think this is a way to milk users and I really don't like this attitude. I think a lot of players already can't resist the temptation to not pay for in-game money for example. I pay like $20 each month. And I'm just one user. How many of us pay for their credits? Isn't that money enough for you?
If you gonna charge money for an API people then will use the scrape method to get info. I'm very sensitive about this greedy milking method as it sounds like a really cheap and greedy way to make more and more money. On top of that it is frustrating developers / coders. It's a step backward in time. You already got some basic API going. Putting up an API on it's own isn't really that hard.. Could be done within one day. No UI design is needed... you just spit out json, Your server loads will drop so that means less costs...LESS. Not more. So what does justify a $5 each month for each API user then? You already make money out if it without people having to pay. This is not the way to go I.M.O. and the proposed idea alone about this makes me feel worried about the whole game. Is the next road section still your passion to create and maintain this game or is it to make quick money?