SOAP and REST: Different Types of API

| 04 April 2019 | Category: General

There’s a lot to think about when you’re looking to integrate an API into your business system or website. From shipping APIs to maps APIS, there are tons of options. One thing you might want to understand before adding an API function is the different types of API.

You’ll find there are two main types of API: SOAP and REST. These different styles are easy for developers to understand, but can be tricky for business people. Learn the differences between these two types of API and see which will work best for your application.

The Basics: What is an API?

API stands for Application Programming Interface. APIs are used in business and development. In simple terms, APIs are a set of routines and protocols that allow one application to plug into the data of another. APIs let two pieces of software “talk.”

A good API can make it easy to do business. A shipping API, for example, can connect a carrier’s software to an ecommerce or business enterprise system. The API connection can be used to exchange information between the two systems. This means a customer can have easy access to real-time shipping information for their purchase within seconds when you use an integrated shipping API with your website or enterprise system.

You might think of APIs as building blocks. In many cases, the code for the API is ready to go. This means it can simply be plugged into a compatible system. APIs make it easy to build apps, as the code is reusable. APIs are essential to the development of softwares and applications.

Just like other softwares, APIs can be both direct and complicated. There are different ways to program APIs, depending on the needs of your application.

What are the Different Types of API?

There are many types of API. Two of them are REST and SOAP. REST is considered an architectural style. SOAP is a protocol. You might find that a REST API can use SOAP protocol, along with HTTP. This means REST and SOAP APIs might look different. They function differently and can be used in different applications.

SOAP and REST APIs each come with different pros and cons. Let’s explore why you might choose one over the other for your application.


SOAP stands for Simple Object Access Protocol. It comes with more security that REST APIs. It offers comprehensive features with extra security in transactions and messages. SOAP is a good choice for business enterprise APIs.

Reasons you might choose a SOAP API include:

  • Extra security: SOAP APIs have tight security. This might apply to your business when you are working with a bank or accepting payments. SSL support is usually built in to a SOAP API and other security features keep data safe.
  • ACID compliance: ACID stands for Atomicity, Consistency, Isolation and Durability. ACID is a method of determining an API’s validity even in the event of errors. This can help protect the database and prevent anomalies.
  • Reliable messaging: Is messaging an integral feature of your software or API? SOAP is important. Not only will messages be more secure, but SOAP features retry logic built in to the API. This provides end-to-end reliability.


REST stands for Representational State Transfer. It is considered a web services API. REST APIs use JSON for data structure and format. This means REST APIs are compatible with web browsers, making them perfect for integrating into a website or ecommerce platform. For developers, REST APIs are based on URIs. URI stands for Uniform Resource Identifier, which is a certain type or URL. REST APIs can be big or small, and are often built to scale. The size of the API depends on what the API is intended to do and how it is built.

Reasons you might choose REST include:

  • Ease of use: Simple and easy to use with a variety of operating systems.
  • Client-services architectures and communication: REST APIs are designed with a client-server principle in mind. They are web APIs.
  • REST APIs are best for the web: REST APIs work great in web applications. JSON is the typical data format. JSON is very compatible with web browsers.

  • Scalable with excellent performance: Technology has come a long way. A REST API can be quick and nimble, and might not bog down your app.

As you can see, there are advantages to both SOAP and REST APIs. You might find that a SOAP API is a good solution for an enterprise system, while a REST API is best for a web services API.

Differences Between SOAP and REST

Along with the differences outlined above, there are a few other ways SOAP and REST differ. Not only is it important to remember that SOAP is a protocol and REST is an architectural style, but the services interface can vary, too.

Four other differences between SOAP and REST are:

  • SOAP requires more bandwidth than REST: Because REST is mostly used for web services, it is lighter and quicker than SOAP. There is more overhead with SOAP.
  • SOAP and REST feature different security: SOAP is designed to work with enterprise level security. Both SOAP and REST work with SSL, but SOAP provides even more secure features. This makes SOAP a good option for financial transactions and more.
  • SOAP and REST allow different data formats: If you use a SOAP API, you need to use XML. REST works with plain text, HTML, XML and JSON.
  • SOAP cannot be cached while REST can be cached: Data can be saved in a cache, which means it can be retrieved for later use. REST allows data to be cached. SOAP does not

You might find that developers lean toward REST APIs when they are building applications for web services. SOAP APIs tend to be selected for enterprise systems. The two types of API both have advantages and can be of use in different situations.

Now that you know a little more about the different types of API, it’s time to plug in and get started. Our shipping API can work seamlessly with your website or enterprise system to provide shipping rate quotes and more.