What is API Description Language

While both SOAP and REST have been used widely to implement Web services and software integration, over time REST has emerged as the predominant approach. REST provides developers with a lower barrier to entry for implementation and greater development flexibility than SOAP. Its architectural conventions and best practices can be integrated into Web services incrementally as opposed to the all-or-nothing adoption of SOAP. In order to achieve generality, SOAP standards are extensive, rigid, and complex. This complexity can lead to implementations that introduce significant overhead on the network bandwidth consumption, execution times, and throughput of SOAP services, especially in the emerging resource-restricted mobile realm. This chapter provides an overview of the logical and physical design of modern Web services and discusses the strengths and weaknesses of the predominant styles. It provides evidence and reasoning behind the emergence of REST as the leader for the development of next-generation Web APIs and services. The chapter also delineates the key technologies that underlie REST and describes emerging and future research directions in support of REST-based APIs and service development.