The central feature that distinguishes the REST architectural style from other network-based styles is its emphasis on a uniform interface between components, which abstracts the information being transmitted. A uniform interface is fundamental to the architecture of any RESTful system. In plain words, this term refers to a generic interface to manage all interactions between a client and server in a unified way. All resources (or business data) involved in the client-server interactions are dealt with a fixed set of operations. The following are the core elements that form a uniform interface for a RESTful system:

• Resources and their identifiers
• The representation of resources
• Generic interaction semantics for the REST resources
• Self-descriptive messages
• Hypermedia as the engine of an application state

Let's look at these items in detail in the following section.