That's a big question. It depends on how you plan to monetize your product and in what space it sits. Also, open doesn't have to mean unregulated. You can (a

That's a big question. It depends on how you plan to monetize your product and in what space it sits. Also, open doesn't have to mean unregulated. You can (and IMO should) have people register for the rights to use your API, and the licensing terms should be that you can revoke their license under certain circumstances. Think of it like Apple vs Android. Apple is super closed off, (wouldn't personally go there for my own product), but Android for a long time was the wild west, some argue it still is. So if you are too open you can actually hurt your products success because too many people provide a poor experience around your product and your product starts to take the blame not the app developer. Whereas with Apple, they try to control so much that it is sometimes impossible to get legitimate apps published timely or at all, even defect fixes can take too much time to get released. I know, I didn't answer really. That's because I really think it depends. However, I would always side on the openness, but openness with some controls to make sure users have a good experience. As for concern over someone writing a better app then you do, I like the attitude overall. If someone does, buy it from them, hire them or use it as motivation to make yours better. Competition is good, it can generally make good things great in the hands of motivated people. As for competitors, execution is what beats competitors. But that doesn't mean you should allow them a front row seat to your party either, hence open but not unrestricted.