Differences Between REST and SOAP APIs

This article discusses the differences between REST and Soap APIs. Therefore, after reading these articles, readers will probably understand why, when and how any of these two APIs are used to develop these APIs. The commonest and most popular keyword is Web Services in the area of Web Development. Herein, we first try to understand what web services are, move towards its concepts and then contradict and contrast these two major types of web services. This article focuses on presenting you with an exhaustive list of differences between the two. This will ensure that you have a clear understanding about which web services type is the best.

Table of Contents

1. What is Web Services?

The IT projects around the world today are being moved to web services based approaches. They have significant benefits for various individuals in different areas of work. For web developers or webmasters and common users, this word has a completely different meaning, usually using the internet as a common user. Web Services is actually a service provided by the World Wide Web (WWW) from digital devices to digital devices for communication. Web technologies like HTTP are used in a web service for communicating data from devices to devices in XML or Json formats from one computer to another. This can be used to apply directly to applications. These systems may include software, objects, posts or documents.

This mechanism can therefore be classified into two different types of communication:

• Simple Object Access Protocol or SOAP
• Representational State Transfer or REST

However, these two classifications are mostly treated the same way. In fact, these two classifications are fundamentally different according to the communication process or behavior.It is worthwhile discussing what are both in fact before addressing the differences between two. The article is presented in a manner where you would get in depth knowledge about each concept.

1.1 What Is a REST API?

REST (Representational State Transfer) is essentially a web services architecture that works as a communication channel between devices or internet systems. There is another term for REST API. The application programming interfaces supported by REST’s style of architecture are termed REST APIs. A web service, database and computer systems compliant with the REST API enable comprehensive access and reshape Web based asset representations by using a predetermined set of stateless protocols and conventional activities. REST API mechanisms produce quick performance, efficiency and much more advancement through these protocols and procedures and the redeployment of the tolerable and updated elements without affecting the system.

1.2 What Is a SOAP API?

It is a conventional communication protocol that enables processes that are communicated through HTTP and XML via different operating systems such as Linux and Windows. SOAP-based APIs are intended which logs such as accounts, passwords, guides and custom objects are created, recovered, updated, and deleted. It makes it easy for API creators to retain their accounts, conduct precise lookups and more, with 20 different types of calls. Then, all those languages supporting web services can be used. SOAP (Simple Object Access Protocol) APIs are reaping the benefits of web – based protocols like HTTP and their XML that operate all operating systems, which makes it easy for its programmers to exploit web services and get responses without any care for language or platforms.

It is important to mention before I move beyond this that SOAP and REST share resemblances with the HTTP, but SOAP is more stiff than REST. The guidelines in SOAP are important, as you can not accomplish any standardized level without these guidelines. REST does not require processing as an architectural style and is of course much more adaptable. In order to exchange information, both SOAP and REST depend on well-written rules, that everyone has agreed to observe.

2. Differences between SOAP and REST

• SOAP means the Simple Access Protocol to Objects. REST stands for REpresentational State Transfer.
• SOAP is an XML – based message protocol, and REST is an architecture style rather than a protocol.
• There is no official standard for REST API, as it is an architectural style. At the other side the SOAP API, because it is a protocol, does have an official standard.
• Multiple standards such as HTTP, JSON, URL or XML are used in REST APIs, while HTTP and XML are mainly the basis of SOAP APIs.
• As the REST API employs multiple standards, it requires less resources and bandwidth than SOAP, which uses XML to create payload and produces a large file.
• Since SOAP is a protocol and REST is an architectural pattern, SOAP can not make use of REST whereas REST may utilize SOAP as the fundamental web services protocol, because it’s only an architectural model at the end.
• There are other ways in which both APIs reveal business logic. REST API uses URL – exposure such as @path(” / WeatherService) “and SOAP API uses interfaces such as @WebService.
• SOAP API describes so many norms, as well as its implementer uses only standard methods to implement them. The outcome becomes an mistake in the event of miscommunication. In contrast, the REST API does not emphasize too many norms and ultimately leads to corrupt API.
• REST messages must be autonomous and help consumers to regulate the communication between the supplier and the end user (for instance, links within a communication in order to decide the next approach). But SOAP has no specifications of this kind.
• SOAP is an XML based messages protocol. REST is stateless and SOAP has specifications for stateful implementation too. Rest does not enforce message format such as XML or JSON or etc. REST does.
• For the purpose of describing the features of the Web services, REST API use Web Application Description Language and SOAP API uses Web Services Description language.
• With JavaScript, REST APIs are much more simple and easy to use. The SOAP APIs with JavaScript are also convenient, but support more execution is not possible.
• SOAP is strongly typed, with rigorous specifications for all implementation parts. But REST provides the principle and the implementation is less restrictive. Thus, compared to the SOAP and end user understanding, REST – based implementation is simpler.
• In order to highlight business rules, SOAP employs interfaces and named operations. REST uses (usually) resources  URI and processes such as (GET, PUT, POST, DELETE).
• SOAP has a series of conventional requirements. WS-Security is the safety parameter in implementing the system. This is a precise benchmark which provides safety regulations for implementing the application. As opposed to SOAP, REST has not for each of these specific concepts. As opposed to SOAP, REST has not for each of such specific concepts. REST is mainly HTTPS based.

3. Benefits of REST Over SOAP

REST offers several other advantages over SOAP in contrast to the simple use of HTTP:

• REST enables more diverse data formats, while SOAP permits XML only.
• In combination with JSON, REST is commonly considered simpler to operate with while it generally fits better with data and provides quicker parsing.
• With JSON, REST provides better browser customer support.
• REST offers high performance, especially by indexing unmodified and not dynamic information.
• REST is the key protocol for major platforms like Yahoo, Ebay, Amazon or Google.
• In general, REST is quicker, with a lower bandwidth. The integration into existing web sites is also simpler without having to refactor web infrastructure. This allows developers to work more efficiently than to rewrite a site from scratch. You can easily add more features instead.

4. Benefits of SOAP Over REST

Some of use cases were more appropriate for SOAP. For example, supporting SOAP for WS – Security can be helpful if you really need more comprehensive security.

• Soap provides certain extra data protection and integrity assurances. They also help to verify ID via intermediaries, instead of only point – to – point, as provided by SSL that is both SOAP- and REST.
• It provides the integrated retry logic to offset unsuccessful communications. REST has a built – in messaging service, on the other hand. If there is a failure in the communication, the customer must try again. No standard REST rule set is also in place. In that way, both parties (service and consumer) must know the content as well as the environment.
• The conventional SOAP HTTP protocol facilitates operation across firewalls and proxy servers with no changes in the SOAP protocol on its own. However, it appears to be slower than the middle ware, like ICE or COBRA, as it uses complicated XML format.
• In addition some cases require more transactional performance and reliability than what can be achieved in HTTP (which restricts REST in this capacity), although this is rarely required. If you really need transactions that comply with ACID, SOAP is the way.
• In certain cases, it may actually be less complicated to build SOAP services than REST. The design of a SOAP service requires fewer programming in the application level for transactions, protection, believe, as well as other components in web services which support complicated transactions which require content and context to maintain.
• Other protocols and technologies make SOAP highly extensible. SOAP promotes WS – Addressing, WS – Coordination, WS – ReliableMessaging as well as a host of other standards for web services in addition to WS – Safety.

5. Comparing use cases for SOAP and REST web services

5.1 When to use REST?

One of the most contentious topics is the use of REST or SOAP in the design of web services. In the following are a few of the key measures which assess when each technology could be used for REST services.

• Limited resources and bandwidth : Since the content of SOAP messages is higher and bandwidth is much greater, REST must be used in cases where the network bandwidth is a restriction.
• Statelessness : REST can be used when a request to another request doesn’t require the maintenance of an information status. If you require an adequate flow of information in which data from one application has to flow into another, then SOAP is more adapted to this. Any online buying site can be taken as an example. Such sites usually require the user to add items to a cart first. In order to conclude the purchase, all cart products will then be transferred to a checkout page. This would be an instance of an application that requires the state functionality. For further processing, the status of the cart products must be transferred to the payment page.
• Caching : Sometimes customers may request several times for the same resource. Sometimes customers may request several times for the same resource. The number of requests sent to the server may be increased. So when the customer asks for a resource, the cache is scanned first. So when the customer asks for a resource, the cache is scanned first. It does not begin to the server if the resources exist. Caching can thus reduce the number of visits made to the Web server to a minimum.
• Ease of coding : Coding and successive execution of REST services is much simpler than SOAP. Therefore, if web services need a fast clinch solution, then REST is the way to get there.

5.2 When to use SOAP?

In the following situations, SOAP can be used:

• Asynchronous processing and subsequent invocation : If the client requires a assurance of reliability and security, the new SOAP 1.2 standard offers many extra features, in particular as equating safety.
• A Formal means of communication : An example is a website where you add items to your cart before you make payments. A perfect example is an online shopping site where customers add products to a cart prior to payment. There is a firm understanding that only the name of the item, unit price and amount are accepted by the web service. There is a company understanding that only the name of the product, unit price and amount are accepted by the web service. In cases where such a scenario exists, the use of the SOAP protocol is often better.
• Stateful operations : In order to support these requirements, the conventional SOAP 1.2 offers the structure WS * if the implementation has a prerequisite that the state is to be preserved from one request to another.

6. Challenges in SOAP vs. REST API

API, which can be used by both clients and servers, is known as the application programming interface. In the client side, the browser offers this facility, while in the server side, it is the web service that can be SOAP or REST respectively.

6.1 Challenges with the SOAP API

• WSDL file : The WSDL document itself is a major challenge to the SOAP API. The WSDL document informs the client about all the activities that the web service can perform. All information including the datatypes used in SOAP messages as well as all procedures available through the Web service is included in the WSDL document. The code snippet below is only part of a WSDL sample file.

<?xml version="1.0"?>
<definitions name="Tutorial" targetNamespace=http://examples.javacodegeeks.com/category/core-java/             
	xmlns:tns=http://examples.javacodegeeks.com/category/core-java/             
	xmlns:xsd1=http://examples.javacodegeeks.com/category/core-java/            
	xmlns:soap=http://schemas.xmlsoap.org/wsdl/soap/
	xmlns="http://schemas.xmlsoap.org/wsdl/"> 

	<types>  
		<schema targetNamespace=http://examples.javacodegeeks.com/category/core-java/
		xmlns="http://www.w3.org/2000/10/XMLSchema">

      	<element name="TutorialNameRequest">    
			<complexType>          
				<all>           
					<element name="TutorialName" type="string"/>         
				</all>       
			</complexType>    
		</element>     
	<element name="TutorialIDRequest">        
		<complexType>          
			<all>           
				<element name="TutorialID" type="number"/>         
			</all>       
		</complexType>      
	</element>   
	</schema>  
</types>	

We have an element called “TutorialName” according to the WSDL file above, which is a string that is portion of the TutorialNameRequest element. Now presume that the WSDL file changes according to the business needs, and the TutorialName becomes TutorialDescription. That would make it necessary for all the clients connected to this web service and make this subsequent transition of their code so that the changes in the WSDL file can be accommodated. The WSDL file, which is the tight relationship between the client and the server, has the biggest hurdle and a modify could have major effect on all user applications.

• Document size : The other major problem is how large the SOAP messages are transmitted to the server from the client. Due to the huge messages, it could be a major issue to use SOAP where bandwidth is a limit.

6.2 Challenges with the REST API

• Lack of Security : No protection like SOAP is imposed by REST. That’s why REST is really suitable for URLs that are publicly available, however REST is perhaps the worst process used for web services in the case of confidential information passing between the client and the server.
• Lack of state : For most Web applications, a static mechanism is required. The customer, which only makes customer applications heavier and difficult to maintain, is unfortunately responsible for maintaining such a state. Regrettably, the buyer is responsible for preserving this state, which only increases and makes it harder to preserve the customer application.

7. Difference between SOAP Vs CORBA Vs DCOM Vs Java RMI

The use of Remote Access Methods like RPC (Remote Procedure Calls) was common prior to arrival of SOAP and REST. The following are the different remote access methods available.

• CORBA : It has been recognized as Common Object Request Broker Architecture. This system is designed to make sure applications developed on different platforms can speak to one another. CORBA was built on an object-based architectural design, however this architecture was not needed for the calling application. The main downside of the methodology would be that the language termed Interface Definition Language must be created in a distinct language and it has only only described an additional language that programmers must learn to use the CORBA mechanism.
• DCOM : This is a open source Microsoft innovation for customers to use remote components for the distributed component object models. Secondly, it was up to the customer to guarantee that whenever the customer sent the request it had to be correctly covered or marked so that the web service could comprehend the request it sent. The customer had to do with this mechanism, which was most important for him. Another problem was if a Java-based application had to operate extra DCOM (Microsoft Technology) code in order to make sure applications constructed in other programming languages can work with a DCOM-based web application.
• Java RMI : This Java implementation was known as the Java Remote Method Invocation, for the way remote objects could be called by remote calls for processes. Java RMI could only be operated on a Java Virtual Machines, the largest limitation of this technology. In order to use Java RMI it is also necessary to run the calling application on the Java frame.

The key differences between SOAP and these methods are:

• Working over HTTP : All RPC methods have a great limit, and the HTTP protocol does not work. Since this Protocol was used by all web applications, this was a big hurdle for customers who had to access RPC-style web services.
• Working with non-standard ports : As RPC-style web services did not operate with the HTTP protocol, distinct terminals had to be opened for customers to access these web services ‘ functionalities.

8. Examples – SOAP vs REST API

8.1 Example of SOAP

A request from the client:

POST http://examples.javacodegeeks.com/cgi HTTP/1.1 
Accept-Encoding: gzip,deflate 
Content-Type: text/xml;charset=UTF-8 
SOAPAction: "http://examples.javacodegeeks.com/Calendar#easter_date" 
Content-Length: 479 
Host: examples.javacodegeeks.com
Connection: Keep-Alive 
User-Agent: Apache-HttpClient/4.1.1 (java 1.5) 2014

8.2 Example of REST

Request:

GET https://examples.javacodegeeks.com/category/software-development/amazon-aws/ HTTP/1.1
Accept-Encoding: gzip,deflate
Host: examples.javacodegeeks.com
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.1.1 (java 1.5)

Response:

HTTP/1.1 200 OK
Date: Fri, 22 Nov 2013 22:32:22 GMT
Server: Apache
X-Powered-By: Phusion Passenger (mod_rails/mod_rack) 3.0.17
ETag: "b8a7ef8b4b282a70d1b64ea5e79072df"
X-Runtime: 13
Cache-Control: private, max-age=0, must-revalidate
Content-Length: 209
Status: 200
Keep-Alive: timeout=2, max=100
Connection: Keep-Alive
Content-Type: js; charset=utf-8
{
   "link": "category\/software-development\/amazon-aws\/36",
   "category": "Category of Software development",
   "a": "Original sin.",
   "position": 36,
   "q": " What is that sinful nature which we inherit from Adam called?"
}

9. Differences Between REST and SOAP – Conclusion

Finally, the most meaningful rest service protocol for the organisation highly depend on the customers you need and the adaptability you want. The one which suits your requirements best is the finest protocol for it. Most of the new APIs are developed using REST and JSON just because it generally absorbs less bandwidth and seems to be simpler to understand both for developing APIs and for other programmers who can write additional services. As most of today’s web browsers ease the consumption of REST+JSON, most public APIs have the default technology. But in certain circumstances, SOAP continues to remain a important protocol.

If you want to learn more about Web Services then check our article on Web Services Interview Questions and Answers

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