Representational State Transfer (REST)
REST is an architectural style for distributed hypermedia systems, originally defined by Roy-Fielding in his 2000 doctoral dissertation. It is built upon the principles of the World-Wide-Web and leverages the HTTP protocol to facilitate communication between a Client-Server architecture.
A RESTful-API is characterized by its adherence to six architectural constraints: Stateless interaction, Cacheable data, a Layered-System, Uniform-Interface, Code-On-Demand, and the separation of concerns. As noted in the original dissertation, these constraints help improve performance, scalability, and simplicity.
In a REST environment, resources are identified by URIs and manipulated using standard HTTP-Methods such as GET, POST, PUT, and DELETE. While JSON is the most common data format used today, XML is also supported. Documentation from MDN Web Docs highlights that REST remains the dominant standard for public Web-Services.