Steven Curtis
4 min readApr 22, 2020

With diagrams: Commands, architecture and networking.

Photo by Toa Heftiba on Unsplash


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CRUD: The four basic functions of persistent storage; create, read, update, and delete

REST (REpresentational State Transfer): architectural style for providing standards between computer systems


REST is a defining set of principles for developing an API. Uses HTTP protocols like GET, PUT, POST and DELETE to link resources to actions within a client-server relationship. The principles of RESTful architectures serve to create an application as a lighter weight alternative to SOAP. APIs may be web-based or designed for specific platforms such as Android or iOS, and a REST API makes it easy to implement other interfaces or applications over time which can turn an initial project from a single application into a platform.

The diagram:

The client may be a web browser requesting weather information in Washington i.e “washington” and receives a JSON string of [“16”]. REST API’s often use result codes (200 = OK; for example)

The six guiding constraints of REST

The client-server mandate

This shows there is a nature of separation between client and server. Services have multiple capabilities and listen for requests which are made by the consumer and accepted or rejected by the server.


Mandates the kinds of commands offered between the client and the server, which is initiated by the request. The request contains all the information necessary for the server to respond.


Server responses are either cacheable or not. A request can be cached by the consumer in an attempt to avoid re-submitting the same request twice.

Interface or uniform contract

RESTful architecture defines a Uniform Contract. This prohibits the use of multiple, self-contained interfaces within an API.