As the Web grows, so does its infrastructure. You don’t have to reinvent the wheel, or single signon. Just find someone else who already built it so you can focus on the pure chocolatey goodness of your own app.
APIs are the glue that gives developers direct access to the services of others, from big guys like Google, Twitter, and LinkedIn to new startups. It’s especially critical in a disaggregated web-based world of cloud and mobile computing.