SOAP vs REST: What's The Difference?

Developers, engineers, and anyone else looking to streamline development and decrease build times for integrations rely on APIs (application programming interface) to enable applications and databases to communicate. This inevitably leads to a comparison between SOAP and REST APIs, since they are two of the most common API paradigms. It can be quite difficult to understand where SOAP and REST methods are best suited, what their specific differences are and why developers prefer one method over the other. In this article we'll take a look at these issues and unpack some of the key considerations when understanding SOAP vs REST.

Differences Between SOAP and REST APIs

The main difference between SOAP and REST is that SOAP is a protocol, while REST can be defined as an architectural style. However, the REST API can use the SOAP protocol. It can also use HTTP. Naturally, they will be presented differently, have different functions, and be employed in different scenarios.

Whether you choose to configure your APIs as RESTful APIs using the REST service or use SOAP requests and messaging depends on the application you're working with. Your programming languages of choice, along with the complexity of your applications (number of endpoints, bandwidth, etc.) will all factor in. 

Let’s take a closer look at each and determine what would make you choose one over the other in tackling the SOAP vs REST question.

Application Programming Interface

Basically, an API is a computing interface that plugs one application directly into the data and services of another. It defines interactions and grants access between multiple pieces of software, allowing them to communicate.

APIs are the base for all mobile applications. They define the calls or requests performed along with how to handle them, what data formats are to be used, and which protocols to follow. An API streamlines IT architectures and makes it easier to share data. You can learn more about API connectivity on the DreamFactory blog.

Simple Object Access Protocol

Simple Object Access Protocol (SOAP) is a protocol all on its own. SOAP is a messaging protocol where SOAP messages contain XML with a header element, body element, and fault element. SOAP is more complex than REST because it defines more standards, such as security rules and the method used to send messages. This can make the back end of SOAP API-management more difficult. Your API-gateway will take more work to set up with more work hours devoted to the develop portal just to keep things going. This extends development lifecycles unnecessarily for most non-enterprise organizations.

The complexity of SOAP also costs a bit more, but might well be worth it for organizations requiring more comprehensive security and ACID (Atomicity, Consistency, Isolation, Durability) compliance features. It is important to mention that SOAP is a good choice for many reasons, but rarely for web services scenarios. Its constraints and features both make it a better fit for enterprise-level situations.

Reasons to build an application with a SOAP API include:

• Tighter security since SOAP uses WS-Security, as well as SSL support for enterprise-level security.
• Schema compliance validation using WSDL (web services description language) to further improve security.
• Accurate retry logic for more reliable message functionality.  
• Built-in ACID compliance, which reduces irregularities and preserves the integrity of a database by defining the interaction of transactions. The more conservative standards of ACID make it a favorite for financial and other highly sensitive transactions.

We can help you understand the use cases and REST-enable your SOAP APIs with our easy-to-use interface. Start your 14-day free trial today!

Representational State Transfer API

Representational State Transfer (REST) can truly be called a “web services” API as it is based on Uniform Resource Identifier (URI), of which URL is a specific type, as well as HTTP protocol. This API mostly uses JSON for a data format because of its superior compatibility with browsers. Theoretically, REST API can also be used with the SOAP protocol.

A REST API can be super simple or massively complex, depending on how it is built, what is added to it and what purpose it is designed for. They are ideal when resources are limited, high security is not required, browser client compatibility is important, and when you need data health and scalability. You can learn how to turn a SOAP web service into a REST API on the DreamFactory blog.

The basics of a REST API include:

• Its beauty is in its simplicity by the use of HTTP protocols.
• Facilitates communication between client, server, and architectures, efficiently passing loads of information.
• Uses single uniform interface, which simplifies interactions between applications.
• Optimized for the internet by using JSON (JavaScript Object Notation) as its data format, instead of XML, making it more browser-friendly with superior performance and scalability.  

In spite of all its benefits, there can be some drawbacks to selecting the REST method. Like any technology, a REST API has the potential to get bogged down or overwhelm your app. Languages such as GraphQL have been created to overcome problems that REST is unable to solve. An open-source tool like Swagger can also be helpful when working with RESTful APIs. All of these need to be evaluated when considering the SOAP vs REST question.

Shorten Your Development Lifecycle

Overall, when you think about APIs for web services, the majority of web developers tend to lean towards REST API architecture. Rare exceptions include when the SOAP protocol is obviously the better option, like for an enterprise app that has many back-end resources, needs ultra tight security, and has other requirements that REST can't provide.

With the right API management tool, you can shorten the development life cycle and simplify the backend developer portals you deal with. Whether you choose SOAP or REST for your APIs, DreamFactory's API management can help remove complexity from your backends and make setting up API gateways that much simpler.

While researching SOAP vs REST, you might also be interested in comparing REST vs GraphQL. Software Planet has penned a great breakdown of these two technologies on their blog.

The DreamFactory platform reduces your lifecycles and improves productivity at every step with an intuitive, seamless interface. With DreamFactory, you can connect all of your applications with ease and no code necessary. DreamFactory even has a SOAP to REST conversion feature so navigating the SOAP vs REST challenge is made even easier! Start your free trial today!