What's the difference between REST & RESTful

What's the difference between a REST system and a system that is RESTful?

From a few things I've read most so called REST services are actually RESTful services. So what is the difference between the two.

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

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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.

REST stands for representational state transfer. That means that state itself is not transferred but a mere representation of it is. The most common example is a pure HTML server based app (no javascript). The browser knows nothing about the application itself but through links and resources, the server is able transfer the state of the application to the browser. Where a button would normally change a state variable (e.g. page open) in a regular windows application, in the browser you have a link that represents such a state change.

The idea is to use hypermedia. And perhaps to create new hypermedia types. Potentially we can expand the browser with javascript/AJAX and create new custom hypermedia types. And we would have a true REST application.

This is my short version of what REST stands for, the problem is that it is hard to implement. I personally say RESTful, when I want to make reference to the REST principles but I know I am not really implementing the whole concept of REST. We don't really say SOAPful, because you either use SOAP or not. I think most people don't do REST the way it was envisioned by it's creator Roy Fielding, we actually implement RESTful or RESTlike architectures. You can see his dissertation, and you will find the REST acronym but not the word RESTful.

REST is an style of software architecture for distributed software

Conforming to the REST constraints is referred to as being ‘RESTful’.

Very used today to build web services as an alternative to SOAP.

Here you have some links to check

http://en.wikipedia.org/wiki/Representational_State_Transfer
http://www.computerworld.com/s/article/297424/Representational_State_Transfer_REST_
http://www.ibm.com/developerworks/webservices/library/ws-restful/

thanks for the answers. Read this article by Alex Rodriguez which suggests that a RESTful web service has 4 basic characteristics which are:

1. Use HTTP methods explicitly.
2. Be stateless.
3. Expose directory structure-like URIs.
4. Transfer XML, JavaScript Object Notation (JSON), or both.

Representational State Transfer (REST) is a style of software architecture for distributed hypermedia systems such as the World Wide Web. The term Representational State Transfer was introduced and defined in 2000 by Roy Fielding[1][2] in his doctoral dissertation. Fielding is one of the principal authors of the Hypertext Transfer Protocol (HTTP) specification versions 1.0 and 1.1. Conforming to the REST constraints is referred to as being ‘RESTful’. Source:Wikipedia

Web services are essentially web sites whose content is consumed by computer programs, not people. REST is a set of architectural principles that stipulate that web services should maximally leverage HTTP and other web standards, so that programs gain all the good stuff that people already can get out of the web. REST is often contrasted with SOAP web services, and other "remote procedure call" oriented web services.

Stefan Tilkov's presentations on REST at Parleys.com are quite good, especially this one.

For a book, you can't get any better than Richardson and Ruby's Restful Web Services.

A service based on REST is called a "RESTful service".

Source I rely on posting that: Dr.Dobbs Archive

There are 4 levels of API defined in the Richardson Maturity Model. These are defined as:

• level 0: any system that has a single endpoint for all its apis(SOAP or RPC fall in this category). Level 0 apis can also resemble "commands".

• level 1: a ResourceUri described system. This is a system that defines multiple entity-based URIs (instead of having a single endpoint like a level 0 systems would). These URIs can use different http actions (POST, GET, PUT, etc) to implement different actions against that resource.

• level 2: aka level 1 w/ a compliant use of Standard HTTP methods/verbs and multi status code responses

• level 3: aka level 2 plus HATEOAS (hypermedia included in the response which describes additional calls you can make)

While levels 1, level 2, and level 3 can be considered as REST systems, only the stricter levels (aka level 2 and level 3) are considered to be RESTful.

So essentially all RESTful apis are REST apis, but not all REST apis are RESTful

definition of the Richardson Maturity Model

Think of REST as an architectural "class" while RESTful is the well known "instance" of that class.

Please mind the ""; we are not dealing with "real" programming objects here.

REST(REpresentation State Transfer) is an architecture using which WebServices are created.

and

RESTful is way of writing services using the REST architectures. RESTful services exposes the resources to identify the targets to interact with clients.

Coming at it from the perspective of an object oriented programming mindset, REST is analogous to the interface to be implemented, and a RESTfull service is analogous to the actual implementation of the REST "interface".

REST just defines a set of rules that says what it is to be a REST api, and a RESTfull service follows those rules.

Allot of answers above already laid out most of those rules, but I know one of the big things that is required, and in my experience often overlooked, as that a true REST api has to be hyperlink driven, in addition to all of the HTTP PUT, POST, GET, DELETE jazz.

A "REST service" and a "RESTful service" are one and the same.

A RESTful system is any system that follows the REST conventions as defined in the original document that created the idea of RESTful networked applications.

It's worth noting there are varying levels of RESTfulness. Overall, REST is a style, not a standard, so there is room for interpretation based on needs. one example is hierarchical resource URLs (e.g. /things/ID/relatedthings) vs flat URLs (e.g. /things/ID and /relatedthings?thing=ID)

REST is an architectural pattern for creating web services. A RESTful service is one that implements that pattern.