SOAP vs. Rest API: What’s the Difference?

Soap vs. Rest API

Application Programming Interfaces (APIs) play a pivotal role in enabling communication and data exchange between various software applications and services. When it comes to communicating with backend servers, SOAP and REST are two of the most common methods. Both of these protocols allow you to send requests and receive responses, but they differ in how they do it. In this article, we’ll cover what REST APIs are, how they work, and some of their advantages compared to SOAP interfaces to help you understand which one might be more suitable for your specific development needs.


SOAP, which stands for Simple Object Access Protocol, is a protocol for exchanging structured information in the implementation of web services. It was initially developed in the late 1990s and has since undergone various iterations to improve its functionality and security. SOAP APIs are known for their strict standards and structured communication patterns.

Key Characteristics Of SOAP API

  1. XML-Based: SOAP messages are typically formatted using XML (eXtensible Markup Language). XML provides a standardized way to structure data—making it easy for different systems, regardless of their operating system or programming language, to understand and process the information.
  2. Protocol-Heavy: SOAP is a protocol-heavy messaging format that takes advantage of well-established protocols like HTTP and SMTP. These extra layers of security help ensure data integrity in mission-critical situations where strict message validation is essential.
  3. Built-in Standards: SOAP was designed to be used in business-to-business communication, so it includes built-in standards for security (WS-Security), transactions (WS-AtomicTransaction), and messaging (WS-ReliableMessaging).
  4. Complexity: Because of SOAP’s strict adherence to standards, its messages tend to be more complex than RESTful ones. This can make SOAP less user-friendly and slower for developers (especially novices) compared with REST.
  5. Strong Typing: SOAP APIs provide strong typing, which can improve the consistency of application code. However, it may lead to longer development times because all data types and structures must be explicitly defined in the service contract.


REST, short for Representational State Transfer, is an architectural style for designing networked applications. Unlike SOAP, REST is not a protocol but rather a set of principles and constraints for building web services. REST APIs have gained immense popularity due to their simplicity, scalability, and compatibility with the web’s existing infrastructure.

Key Characteristics Of REST API

  1. Resource-Based: REST APIs are centered on the concept of resources, which can be any object or single piece of data. Each resource is identified by a unique URL (Uniform Resource Locator), and interactions with these resources are performed using standard HTTP methods such as GET, POST, PUT, DELETE, etc.
  2. Stateless: REST is inherently stateless. Each request must contain all necessary information to process it; no session data can be stored on the server side (with some exceptions). This means that every single request has to contain some sort of unique token or identifier in order to identify which user made that request.
  3. JSON or XML: While REST allows for flexibility in data formats, it is associated with JSON (JavaScript Object Notation) or XML (eXtensible Markup Language), lightweight markup languages that enable the easy exchange of structured data.
  4. Simplicity: REST APIs are known for their simplicity, making them easy to understand and use. This can lead to faster development times and easier debugging when compared with other API styles, such as SOAP.


Now that we have a clear understanding of SOAP and REST APIs, let’s compare them in various aspects to help you make an informed choice for your specific application:

1. Ease of Use and Development

REST has become the most popular method because it is easy to use, unlike SOAP. The latter requires developers to learn a new language (XML), which makes it hard for people without programming skills or experience to create their own applications. With REST APIs, all you need is JSON data transmitted over HTTP(S).

2. Flexibility

A major advantage of using REST APIs over SOAP-based ones is that they are more flexible since they allow you to make changes quickly without affecting other parts of your system as long as there aren’t many interconnections among services/resources being used by different applications running at the same time within one server environment (i.e., cloud).

3. Performance

The performance of RESTful APIs is better than SOAP-based ones since they don’t require you to parse a lot of XML data before making any decision. RESTful APIs use lighter-weight HTTP requests that don’t require a lot of processing power. In addition, the overhead in terms of bandwidth and CPU usage is also lower when compared to SOAP-based APIs.

4. Security

The security of SOAP-based APIs is more secure than RESTful APIs due to the fact that they use XML signatures for authentication. However, RESTful APIs are not completely unsecured since they can use OAuth 2.0 or JSON Web Tokens (JWT) for authentication purposes.

5. Compatibility

Both SOAP-based and RESTful APIs are compatible with most of the popular programming languages like Java, C#, Go, Python, etc. However, when it comes to mobile app development, RESTful APIs are more popular since they are lightweight and easy to use on mobile devices. On the other hand, SOAP APIs work better with legacy system integrations.

6. Scalability

RESTful APIs are more scalable than SOAP-based APIs due to the fact that they use fewer resources and make it easier for developers to add new features or fix bugs. The main reason why SOAP-based APIs are not scalable is that they require a lot of time and effort when coding changes into the existing infrastructure.

7. Use Cases

Both RESTful APIs and SOAP-based APIs are used for different use cases. For example, if you want to build a mobile app or a website that needs to interact with other systems, then RESTful APIs would be a better choice. On the other hand, if you want an API to connect your legacy system with newer technologies such as cloud computing or machine learning, then SOAP-based APIs are more suitable.


The key difference between SOAP and REST APIs is in their style of communication. SOAP is an XML-based protocol that uses HTTP requests to send data between systems, while REST uses JSON objects with the same structure as a URL path. In some cases, a hybrid approach that combines the strengths of both SOAP and REST might be the best solution. Both have advantages and disadvantages, but it’s important to understand the nature of your application, your development team’s expertise, existing infrastructure, and your long-term goals before making decisions about which one would work best for your application or organization.

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