SOAP VS REST APIs: What Are They & Why Should You Care?

Ever wondered how your favourite applications are talking to each other behind the scenes? Whether it’s your favourite streaming platform remembering your watch history or your phone’s weather app giving you real-time local forecasts wherever you are in the world. 

This is the invisible magic we call Application Programming Interface, or as it’s more commonly known, APIs.

SOAP and REST are two internet data exchange mechanisms with different approaches to API design. The SOAP approach is highly structured and uses the XML data format. However, REST is more flexible and allows applications to exchange data in multiple formats.

What Is An API?

An API (Application Programming Interface) acts as a bridge between two different systems. The API allows one application to request information or send instructions to another system or application, without needing to know the ins and outs of that system.

Some Examples Of APIs 

Your mobile phone’s weather needs to display weather updates in real time. Rather than collecting and processing that data itself, the app can use a weather service API to fetch the latest forecasts in real-time. This speeds up the data processing, allowing you to see to-the-second updates to your mobile devices.

Similar to the weather app, a shopping website uses a payment API to process your credit card. Many different types of payment APIs can collect and use your data to pay for your products online. This can include transaction APIs, subscription APIs, payout APIs, and even delivery mapping APIs, each serving a specific purpose in the payment and product lifecycle.

APIs are everywhere. They’re what allow different platforms, tools, and devices to talk/send to one another. Helping you in everyday life. 

What Is A REST API?

REST (Representational State Transfer) is an architectural style. It is the perfect API for building web and mobile apps where speed and future scalability matter. It’s also a lighter, faster and more flexible way of using standard web protocols such as HTTP and data formats such as JSON. 

The Key Benefits Of A REST API

Statelessness

The server doesn’t need to store any information about the client’s state. Rather than storing session information, a client would provide all the necessary details in its request.

Layered Architecture

All REST API software is architected and is split into layers with a distinct purpose, helping to keep your systems modular and maintainable.

Cache Support

Responses are cached on the client side to enhance the performance of the application, which helps by eliminating the necessity to reprocess repeated requests.

Consistent Interface

HTTP methods like POST and DELETE will help make the interactions between clients and servers consistent and simple.

What Is A SOAP API?

SOAP (Simple Object Access Protocol) is a protocol that relies on XML and strict messaging standards. It’s highly secure and reliable, often used in large or financial systems where formal contracts and data validation are an everyday essential. 

The Key Benefits Of A SOAP API

SOAP is less flexible than REST because it has a strict set of XML rules it must adhere to. While SOAP APIs are commonly used for developing private APIs for internal business functions, they can also be used for public-facing APIs and applications.

Enhanced Security

SOAP APIs are incredibly secure because they authenticate and authorise API calls to ensure information is passed only to the correct software or users. These APIs can use any underlying transport protocol, but the most common is HTTP, allowing them to use other authentication processes on top of its existing security features.

More Reliable Transactions

SOAP is more secure than REST because it uses encryption to protect the transfer of data, which helps to make it a more reliable API. In addition, the built-in security features of SOAP prevent message corruption or unauthorised access to your system or software. 

Less Coding

SOAP can be less complex than REST, requiring less coding for more security. However, SOAP typically has a higher learning curve than REST and is more challenging to code because it requires adherence to strict XML standards.

When Should My Company Use Both REST & SOAP APIs

Although REST is more common, there are reasons to use SOAP, especially in larger businesses. Using both REST and SOAP APIs can be beneficial when your business has to meet different technical requirements or work across legacy and modern systems. Some examples of companies in the UK that are using both REST & SOAP APIs are:

The NHS employs SOAP to store all hospital patient records, ensuring that they can be easily accessed by doctors and GPs throughout the UK. But they also use REST for mobile applications, for example, on the new NHS mobile app, where we can view our appointments and medications as real-time data.

What Should You Consider Before Choosing REST & SOAP

Are you unsure whether to use REST, SOAP, or a combination of the two? Well, to help you decide, we’ll take a look at some key factors that will influence your decision. 

What Kind Of Systems Are You Working With?

If you’re building something modern like a mobile or web app, REST is usually the solution that many software agencies will choose. If you’re connecting to something older, SOAP will generally be used, as it is more suitable for those systems.

How Important Is Security For APIs?

Both SOAP & REST are secure, but SOAP has more built-in features for handling things like authentication and encryption. REST is still a safe API, but it often relies on extra tools like HTTPS or tokens.

Do You Need Flexibility Or Structure?

If you’re looking for flexibility, REST is the answer. It provides the option to use data formats such as JSON or XML, making it easier to work with. SOAP sticks to XML, which is more rigid and more reliable.

What Do Your Clients Or Partners Expect?

Sometimes the choice is made for you; if a partner system only supports SOAP, that’s what you’ll need to use. Other times, your team or users might prefer REST for its simplicity.

Want Help Mapping Out The Right Integration Strategy?

We assist businesses in designing future-proof systems that integrate seamlessly with both legacy and modern technologies, creating tools tailored to your business needs. 

We blend technical expertise with a robust business understanding. Working hand-in-hand with your business, we restructure working practices, reduce spend and deliver a competitive edge.

Need help with an API? Get in touch with our team, and we’ll help you plan it out.

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