No, that sounds like what consultants would do on an integration project, but not at all how software development works. Sure, you call APIs - after you write them. Which comes after you define what connections are needed between various layers of the system, which odds are you are also writing.
Saying that most software development is done by calling APIs is like saying that most driving of cars is done by moving your hands to the left and the right. Sure, that is an important piece of what is going on, but it really misses the bigger picture.
