RESTful APIs make programming easy for users, but it can be tricky to map traditional APIs to REST expectations. While REST simplifies user expectations, getting the flow and granularity of data right remains a challenge. REST's popularity has led to tremendous growth in "almost REST" APIs, and grown demand for projects that evolve toward the hypermedia possibilities REST opens for data on the Web. §This book shows readers how to get APIs as close as possible to optimum usability, focusing on solutions to common problems that cross a variety of domains. By combining the tools and expectations that the Web has already provided with complex data structures, developers will be able to create secure and powerful applications their customers will be happy to use.