What is the different between RESTful and RESTless

'RESTless' is a term not often used.

You can define 'RESTless' as any system that is not RESTful. For that it is enough to not have one characteristic that is required for a RESTful system.

Most systems are RESTless by this definition because they don't implement HATEOAS.

Any model which don't identify resource and the action associated with is restless. restless is not any term but a slang term to represent all other services that doesn't abide with the above definition. In restful model resource is identified by URL (NOUN) and the actions(VERBS) by the predefined methods in HTTP protocols i.e. GET, POST, PUT, DELETE etc.

REST stands for REpresentational State Transfer and goes a little something like this:

We have a bunch of uniquely addressable 'entities' that we want made available via a web application. Those entities each have some identifier and can be accessed in various formats. REST defines a bunch of stuff about what GET, POST, etc mean for these purposes.

the basic idea with REST is that you can attach a bunch of 'renderers' to different entities so that they can be available in different formats easily using the same HTTP verbs and url formats.

For more clarification on what RESTful means and how it is used google rails. Rails is a RESTful framework so there's loads of good information available in its docs and associated blog posts. Worth a read even if you arent keen to use the framework. For example: http://www.sitepoint.com/restful-rails-part-i/

RESTless means not restful. If you have a web app that does not adhere to RESTful principles then it is not RESTful

Here are roughly summarized the key differences between RESTful and RESTless web services (it does not have to be strictly valid):

1. Protocol

• RESTful services use REST architectural style,
• RESTless services use SOAP protocol.

2. Business logic / Functionality

• RESTful services use URL to expose business logic,
• RESTless services use the service interface to expose business logic.

3. Security

• RESTful inherits security from the underlying transport protocols,
• RESTless defines its own security layer, thus it is considered as more secure.

4. Data format

• RESTful supports various data formats such as HTML, JSON, text, etc,
• RESTless supports XML format.

5. Flexibility

• RESTful is easier and flexible,
• RESTless is not as easy and flexible.

6. Bandwidth

• RESTful services consume less bandwidth and resource,
• RESTless services consume more bandwidth and resources.