Today, it seems like every app connects and integrates with the next. We can check out via PayPal, login via Facebook, and share content across all of our social media platforms at once. This interconnectedness helps people get more done in less time, leads to rapid growth for relatively young product companies, and creates a supportive ecosystem of well-crafted, well-tested applications. And all of it thanks to the essential bond, the tie that binds: the API (application programming interface).