Whether you are working with enterprise software, social networks, the Internet of Things, or various consumer-based applications, interoperability through easy-to-use APIs is crucial for product success.We will tour through some consumer product API documentation sets, like those of Twitter, Flickr, Facebook, and others, and see what works and what does not. We will look at how tools like Swagger are used to demonstrate and document APIs. Learn how to advocate for a usable API design and to develop good API documentation from the beginning.