What are the differences between REST and SOAP?

How should I implement services for my company? Should they be based on REST or on SOAP? What are the differences?

Choosing between both options is still a challenge for some companies that are still not familiar with the strengths and weaknesses of each one. In this article we will briefly go over:

• What is SOA?
• What is REST Web Services and what is it for?
• What is SOAP Web Services and what is it for?
• REST vs. SOAP: What are their differences and advantages?

In this short post, we will try to help you make a more confident decision as to which option is better for your business. Let’s go!

What is SOA?

Well, firstly it is important to emphasise that SOAP is not the same as SOA. We know that sometimes it can lead to confusion, because they are similar terms but with quite different meanings.

-SOA: The perfect architecture to adapt to business needs-

SOA (Service-Oriented Architecture) is a type of software architecture, which is based on the integration of applications through services. These services are used to build: compositions, BPM, proxies and even APIs. But aren’t REST and SOAP also services? Yes, they are technologies that apparently offer the same functionalities, but they do not do the same thing, although both REST and SOAP follow the same SOA architecture, so they both follow the same “principles”.

-This post is so interesting: SOA Architecture, what are its benefits to my company’s IT?-

With this understood, it is time to know explore the differences between SOAP and REST, and learn about their features.

What is REST Web Services and what is it for?

REST (Representational State Transfer) is a software architecture style aimed at distributed hypermedia systems such as the web. This term refers specifically to a collection of principles for the design of network architectures.

There are several projects that can benefit from a REST architecture. In particular, those for which the server requests are made by the client, based on a relevant resource.

It is important for a REST architecture to comply with 6 principles.

• Client – Server
• Uniform Interface
• Cacheable
• Stateless
• Layered
• Code-on-demand

In order to dive deeper into these concepts, you can find more information here.

REST advantages

• Among its advantages are the possibility of creating client/server in different languages. It gives us the possibility of sending information in different formats, although JSON is usually used. In terms of performance, it is better than SOAP services. Due to its lightness and the possibility of easily caching calls through HTTP control headers.
• Therefore REST allows us to create lighter and simpler services, easily visible and usable through any web browser. As a result, it has overtaken SOAP in more informal business environments.
• REST is lighter compared to SOAP, which can make it a better choice for mobile applications and other resource-constrained environments.
• RESTful APIs can easily scale to meet the demands of large-scale applications because they do not require any session state to be stored on the server.
• REST allows developers to work with a variety of programming languages and frameworks, making it more flexible than SOAP.

Disadvantages of REST

Among its disadvantages is that although the use of HTTP methods is widely known, there is no standard as such that tells us how to perform these methods, unlike SOAP. And a REST web service also does not generate a contract between client and server by default, although we can do it as an add-on. Compared to SOAP, they are less secure APIs. And in general, the processing of large blocks of data or the impossibility of making more than one call per connection are other drawbacks. Although these last two have been solved with the arrival of the HTTP 2.x protocol and its implementation by RESTful services.

REST Use Cases: Specific Situations REST can be used for

• Developing public APIs: REST APIs are ideal for creating public web services because they are easier to use and adopt than SOAP APIs. They are also more flexible in terms of data formats, which makes them a good choice for working with public data and services.
• Work with limited server resources and bandwidth: REST APIs are stateless, which means that each interaction is independent and the server does not store information about previous requests. This greatly reduces the amount of server memory required and improves performance, making REST a good choice for working with limited server resources and bandwidth.
• Building mobile applications: REST is lightweight, efficient, stateless and cacheable, making it ideal for building mobile applications that need to access data from a server. In addition, REST APIs can use different data formats, such as JSON, which is lighter than XML, making them faster and more efficient than most SOAP APIs.
• Build microservice architectures: Microservices are a way of developing software systems by creating small, independent services that work together to form a larger application. Since each microservice usually has a specific, well-defined function and interacts with other services through APIs, REST is a natural solution for communication between services. RESTful APIs allow each microservice to expose its functionality as a web service, which can be easily consumed by other microservices or by client applications. Moreover, because REST is stateless, it is ideal for handling a large number of simultaneous requests, which is important in highly distributed architectures.

What is SOAP Web Services and what is it for?

Now that we know what REST services are, it is important to also understand SOAP or Simple Object Access Protocol services.

SOAP is a protocol for the exchange of messages over computer networks, generally using HTTP. This protocol is based on XML, making it easier to read, even if messages are longer and therefore considerably slower to transfer. These could be some reasons to use SOAP, instead of REST.

We can find several types of message models in SOAP, but the most common is RPC, where the intersecting point of a message between the client and the server results immediately in the response of a message to the client.

Google, Facebook and many banking organisations are some of the major websites that currently use applications that implement web services.

SOAP advantages

• Among its advantages we can find that, as it works through the TCP transport protocol, it is possible to use different application protocols such as: HTTP, SMTP or JMS. It also gives us the possibility to generate client/server in different programming languages. And it is widely standardised, so there are concrete rules to form the message, the contract between client/server or the format of the data to be sent, always XML.
• Because of these features, SOAP is widely used in enterprise environments. Where a clear contract between client and server is required, and security of communications is very important.
  SOAP is designed to allow integration between different systems and programming languages, which means that the exchange of information between different systems and platforms can be automated.

Disadvantages SOAP

• Among its disadvantages is that, as it is largely standardised, it is not very flexible and there tends to be many errors when developing if these standards are not known. As it uses the TCP protocol, it also has a worse performance than other types of Web Services.
• For these reasons it is important to have a product that helps in the creation of SOAP APIs such as the Enterprise Service Bus, see related article, or a company that specialises in developing them, such as Chakray.
• SOAP can be complex to implement and use, which can make it difficult to adopt for simpler applications.
• Due to its focus on security and reliability, SOAP can be slower than other communication protocols such as REST.

SOAP Use Cases: Specific situations SOAP is useful for

• Developing private APIs for large enterprises: SOAP is a good option for developing private APIs, especially for large enterprises, because it provides advanced web security and transaction management mechanisms, making it ideal for enterprise solutions.
• Working with stateful transactions: If you need to work with chained or repetitive transactions, such as bank transfers or online order processing, SOAP is a good option. Although this requires more server resources and bandwidth, it can be very useful if you need to store information about the client on the server and use it in a series of requests.
• Use an underlying transport protocol other than HTTP: Unlike REST, SOAP is independent of the underlying transport protocol and can be used with any protocol, such as SMTP or JMS. Therefore, if you need to use a transport protocol other than HTTP, SOAP is a good choice.

WebSockets

First of all, we must understand that when we create an API with WebSocket, we are not creating an API with WebServices itself. We have to understand that it is another technology and therefore we could implement both types of API within the same application.

It is a technology that allows instant messaging between two machines that have previously established a connection. It is based on three main characteristics:

• TCP Socket: Communication is established persistently through a single channel.
• Bi-directional: Both machines can send messages to each other.
• Full-duplex communication: Communication can take place in both directions at the same time and independently of the state.

It is also widely supported by web browsers. In this way we can create truly dynamic websites, in which the client and server can communicate in real time, creating a more interactive and therefore more satisfying web experience.

Among its advantages is, as we have said, that it is especially designed for the creation of applications or websites with real-time utilities. Improving performance in terms of response times and the management of large messages, compared to other web services over HTTP/1.1.

On the other hand, if the connection is to be established through proxies, it may not be supported by some of them. The need to implement control mechanisms in case of failures during message transmission. And finally, with the advent of HTTP/2 and Server-Sent Events (SSE) technology, the difference in performance and unique features is reduced.

Now is easier to understand what REST and SOAP services are, we can go deeper into the advantages of each of these concepts, and into how we can apply them to our own situation.

REST vs SOAP: What are the differences and advantages?

The main differences between SOAP and REST web services are:

Conclusion: SOAP vs REST, who will win?

In conclusion, REST and SOAP are two communication protocols used on the web with different approaches to data exchange. REST focuses on simplicity and horizontal scalability, which makes it suitable for web and mobile applications. On the other hand, SOAP focuses on reliability and vertical scalability, which makes it suitable for enterprise and mission-critical applications that require high security and reliability. Both protocols have advantages and disadvantages, and the choice between them depends on the specific needs of the project in question. It is important to note that the choice of the right communication protocol can have a significant impact on the performance and scalability of an application.

Although SOAP has been popular in the past, some companies find it too complex and inflexible. REST, on the other hand, is known to be a simpler and more flexible alternative, better suited to the requirements of certain applications. For this reason, more and more companies are turning to REST-based services to handle large amounts of data in a simple and scalable way. Although both architectures have their defined niches, it is important to keep in mind that the choice of the right communication protocol can have a significant impact on the performance and scalability of an application. Therefore, it is important to assess the specific needs of the project in question before choosing between REST and SOAP.

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