Don't let people confuse you with their comments. You've tapped the correct door for a right question. API development is a part of System development. Without API development there's no way to "tap" the computer (or to be more precise: OS). For example: Without the API-Packages (JAVA, C++, C#, PYTHON, etc.) the number of developers could shrink to a bunch of REAL developers. In short:
- API development is the bone, the foundation for the
- Application developers.
Hence, API developers are usually more versed and more knowledgeable than Application developers (who have to use the works of API developers to create their apps).
When you read the comments on this forum you may see lots of "developers" just build their apps around existed APIs. I myself rarely see a member of this forum posted his/her own API for the others to use.
Hope that you see the difference and choose the right "door"