Since the beginning of software, we have bundled frequently-used functionality into libraries -- both our own, and those created by third parties. APIs tell software developers how to use a library, and make it possible for developers to treat libraries as black boxes, considering only what the library does, not how it does it.
Today, as software moves increasingly to the Web, APIs and libraries are also moving to the Web. This means that you can now outsource, by means of Web APIs, a huge amount of your application's functionality.
What does this mean for software developers? What does this mean for the future of software development? In this talk, I describe the past, present, and future of APIs, and how I believe the Web is changing the landscape.