What's the difference between REST & RESTful

Representational state transfer (REST) is a style of software architecture. As described in a dissertation by Roy Fielding, REST is an "architectural style" that basically exploits the existing technology and protocols of the Web.

RESTful is typically used to refer to web services implementing such an architecture.

REST based Services/Architecture vs. RESTFUL Services/Architecture

To differentiate or compare these 2, you should know what REST is.

REST (REpresentational State Transfer) is basically an architectural style of development having some principles:

• It should be stateless

• It should access all the resources from the server using only URI

• It does not have inbuilt encryption

• It does not have session

• It uses one and only one protocol - HTTP

• For performing CRUD operations, it should use HTTP verbs such as get, post, put and delete

• It should return the result only in the form of JSON or XML, atom, OData etc. (lightweight data )

REST based services follow some of the above principles and not all

RESTFUL services means it follows all the above principles.

It is similar to the concept of:

Object oriented languages support all the OOP concepts, examples: C++, C#

Object-based languages support some of the OOP features, examples: JavaScript, VB

Example:

ASP Dot NET MVC 4 is REST-Based while Microsoft WEB API is RESTFul.

MVC supports only some of the above REST principles whereas WEB API supports all the above REST Principles.

MVC only supports the following from the REST API

• We can access the resource using URI

• It supports the HTTP verb to access the resource from server

• It can return the results in the form of JSON, XML, that is the HTTPResponse.

However, at the same time in MVC

• We can use the session

• We can make it stateful

• We can return video or image from the controller action method which basically violates the REST principles

That is why MVC is REST-Based whereas WEB API supports all the above principles and is RESTFul.

"REST" is an architectural paradigm. "RESTful" describes using that paradigm.

As Jason said in the comments, RESTful is just used as an adjective describing something that respects the REST constraints.