Difference Between SOAP vs REST Web Services

1. Overview

In this post, we will learn the difference between SOAP vs REST Web Services in detail. If you are new to REST then read our RESTful Tutorial.
Unfortunately, there are a lot of misinformation and misconceptions around REST.

SOAP and REST can't be compared directly since the first is a protocol (or at least tries to be) and the second is an architectural style. This is probably one of the sources of confusion around it since people tend to call REST any HTTP API that isn't SOAP.

A SOAP client works like a custom desktop application, tightly coupled to the server. There's a rigid contract between client and server, and everything is expected to break if either side changes anything. You need constant updates following any change, but it's easier to ascertain if the contract is being followed.

A REST client is more like a browser. It's a generic client that knows how to use a protocol and standardized methods, and an application has to fit inside that. You don't violate the protocol standards by creating extra methods, you leverage on the standard methods and create the actions with them on your media type. If done right, there's less coupling, and changes can be dealt with more gracefully.

However, we can find how REST differs from SOAP. Let's list Difference Between SOAP vs REST Web Services

2. Difference SOAP vs REST Web Services.

3. When to use REST and when to use SOAP

One of the most highly debatable topics is when REST should be used or when to use SOAP while designing web services.
Below are some of the key factors that determine when each technology should be used for web services REST services should be used in the following instances
  • Limited resources and bandwidth – Since SOAP messages are heavier in content and consume a far greater bandwidth, REST should be used in instances where network bandwidth is a constraint.
  • Statelessness – If there is no need to maintain a state of information from one request to another then REST should be used. If you need a proper information flow wherein some information from one request needs to flow into another then SOAP is more suited for that purpose. We can take the example of an online purchasing site. These sites normally need the user first to add items which need to be purchased to a cart. All of the cart items are then transferred to the payment page in order to complete the purchase. This is an example of an application which needs the state feature. The state of the cart items needs to be transferred to the payment page for further processing.
  • Caching – If there is a need to cache a lot of requests then REST is the perfect solution. At times, clients could request for the same resource multiple times. This can increase the number of requests which are sent to the server. By implementing a cache, the most frequent queries results can be stored in an intermediate location. So whenever the client requests for a resource, it will first check the cache. If the resources exist then, it will not proceed to the server. So caching can help in minimizing the number of trips which are made to the web server.
  • Ease of coding – Coding REST Services and subsequent implementation is far easier than SOAP. So if a quick win solution is required for web services, then REST is the way to go.
SOAP should be used in the following instances

  • Asynchronous processing and subsequent invocation – if there is a requirement that the client needs a guaranteed level of reliability and security then the new SOAP standard of SOAP 1.2 provides a lot of additional features, especially when it comes to security.
  • A Formal means of communication – if both the client and server have an agreement on the exchange format then SOAP 1.2 gives the rigid specifications for this type of interaction. An example is an online purchasing site in which users add items to a cart before the payment is made. Let's assume we have a web service that does the final payment. There can be a firm agreement that the web service will only accept the cart item name, unit price, and quantity. If such a scenario exists then, it's always better to use the SOAP protocol.
  • Stateful operations – if the application has a requirement that the state needs to be maintained from one request to another, then the SOAP 1.2 standard provides the WS* structure to support such requirements.

4. Conclusion

In this post, we have learned the difference between SOAP vs REST Web Services. Also, we have seen when to use REST and when to use SOAP.
Read our more popular RESTful Tutorial.


  1. This is an awesome post. Really very informative and creative contents. This concept is a good way to enhance knowledge. I like it and help me to development very well. Thank you for this brief explanation and very nice information. Well, got good knowledge.
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