The Six REST Principles

The Six REST Principles

1. Stateless

   • Make all client-server interactions stateless
   • Whatever client HTTP requests that are being made should not be stored by the server
   • No new/old sessions to recover
   • Each request from the client should contain all the information necessary to service the request

2. Client Server

   • The client application and server application must be able to evolve separately without being dependant on one another
   • The client should only know the resource URIs
   • To be kept simple

3. Uniform Interface

   • The resource in the system should have only one logical URL, which should provide a way to fetch related or additional data
   • Any single resource should not be too large
   • The resources must be relevant and should contain links (HATEOAS) pointing to relative URLs to fetch related information
   • Must decide APIs interface for the resources within the system which are exposed to API consumers

4. Code on Demand

   • This is optional
   • Optionally includes a "return executable code" to support a part of the web application

5. Cacheable

   • Should be applied to resources when applicable
   • The resources must declare themselves cacheable
   • Caching improves performance for the client and better scalability for a/the server because the load as reduced

6. Layered System

   • For example, placing APIs on server A, storing data on server B, and authenticate requests in server C