In this article, we look at the major differences between SOAP and REST. OOPS.. actually, comparing the two is a little like comparing apples to oranges, as SOAP is a protocol format based on XML, whereas REST is an architectural approach.
You will Learn
- What is REST?
- What is SOAP?
- How are REST and SOAP different?
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This is the second article in a series of articles on REST APIs:
- 1 - Introduction to REST API - RESTful Web Services
- 2 - REST v SOAP - A few perspectives
- 3 - Designing REST API - What is Contract First?
- 4 - Designing REST API - What is Code First Approach?
- 5 - REST API - What is HATEOAS?
- 6 - REST API Best Practices - With Design Examples from Java and Spring Web Services
REST vs SOAP
REST vs SOAP are not really comparable. REST is an architectural style. SOAP is a message exchange format.
Let’s compare the popular implementations of REST and SOAP styles.
- RESTful Sample Implementation : JSON over HTTP
- SOAP Sample Implementation : XML over SOAP over HTTP
At a high level, SOAP is about restrictions on your message structures while REST is an architectural approach focused on using HTTP Transport.
- SOAP is particular about the Data Exchange Format. With SOAP, this is always SOAP-XML, which is an XML with envelope, header and body. Both the request and response should adhere to the SOAP structure.
- REST is very particular about using HTTP as the transport protocol. It intends to make the best use of the features provided by HTTP - Request methods, Request headers, Response, Response headers etc.
Message interchange format
- With SOAP, you use SOAP XML format for Request and Response
- With REST, there is no such fixed format. You could exchange messages based on XML, JSON or any other convenient format. JSON is the most popular among the used formats.
- SOAP makes use of Web Service Definition Language (WSDL).
- REST does not have a standard service definition language. Even though WADL was one of the first standards to be proposed, it is not very popular. Swagger or Open API is another popular approach.
- SOAP does not place any restrictions on the kind of transport protocol. You could either use Web (which is HTTP), or MQ.
- REST intends to make the best use of HTTP Transport Protocol
Ease of Implementation
RESTFful services are typically a lot easier to implement than SOAP based web services.
- REST typically uses JSON, which is easier to parse and process. In addition to that, REST does not require you to have a service definition in place to provide a web service.
- However with SOAP, you are needed to define your service using WSDL, and greater overhead is involved in processing and parsing the SOAP-XML messages.
Do check out our video on this:
In this article, we broadly looked the differences between REST and SOAP.