OAuth and webhooks and rate limits, oh my! Public APIs can add powerful features and functionality to your web app—creating value for your users better or faster than what you can build yourself. But what if you're unfamiliar with public APIs or mostly engineer on a core product? In this talk, we'll dissect a variety of mechanisms common in public APIs. You'll leave with a newfound ability to build with public APIs, ready to use internet LEGOs to build something splendid.