SOAP vs. REST: Which API Design is Right for Your Business?

According to Slashdata, nearly 90% of developers use APIs in some capacity. APIs enable developers to efficiently build software applications by abstracting away the complexity of low-level software layers—allowing developers to focus on core functionalities.

Whether you’re a business or IT professional, understanding the nuances of API development is crucial for your organization’s success. There are two main API building methods: SOAP and REST. These methods differ significantly in their approaches and characteristics, each with its own set of advantages and considerations.

What is SOAP?

SOAP, or Simple Object Access Protocol, is a protocol-based approach to API development. It follows strict rules for communication, using XML as its message format. SOAP APIs are known for their structure, built-in error handling, security features, and stateful capabilities.

What is REST?

REST, which stands for Representational State Transfer, is an architectural style for building APIs. It’s all about simplicity and flexibility. REST APIs use various formats for message exchange, including JSON and XML. They are inherently stateless and rely on the underlying transport protocol, usually HTTP, for security and error handling.

SOAP vs. REST: Which API Suits Your Business?

The way APIs handle communication, message formats, state management, error handling, and security can significantly impact your development process and the performance of your applications. SOAP, a protocol-driven approach, and REST, an architectural style, offer distinct features that are worth exploring.

Communication: Protocol vs. Architectural Style

SOAP is a protocol that mandates a set of rules for communication. It relies on request and response messages, typically transmitted over HTTP, SMTP, or TCP. In contrast, REST is an architectural style that doesn’t dictate a particular protocol. It takes advantage of existing protocols, primarily using HTTP methods like GET, POST, PUT, and DELETE.

In an enterprise-level inventory management system real-time communication between servers and client applications is crucial. SOAP would be ideal, as it defines a clear communication protocol, ensuring that data integrity and consistency are maintained.

On the other hand, if you are developing a public-facing e-commerce website, REST’s architectural style, which leverages standard HTTP methods like GET, POST, PUT, and DELETE, would provide the necessary flexibility to interact with different clients and platforms while taking advantage of existing web protocols.

Message Format: XML vs. Multiple Formats

SOAP exclusively uses XML for message formatting, which ensures strict structure and data typing. REST, on the other hand, allows for multiple formats, including JSON, XML, and HTML. This flexibility can be a game-changer, especially in diverse development environments.

A financial application requiring accurate and strict data representation, would be best suited to SOAP. SOAP, with its reliance on XML, ensures that financial transactions are consistently formatted, reducing the chances of data interpretation errors.

In contrast, if you’re developing a social media platform, REST’s support for multiple message formats like JSON, XML, and HTML allows you to cater to a wide variety of clients, including web browsers, mobile apps, and third-party integrations, making it a versatile choice.

State Management: Stateless (with options) vs. Stateless

SOAP can be either stateful or stateless, depending on how you configure your API. In contrast, REST is inherently stateless, which simplifies server and client communication. However, this means you may need to manage states manually if required.

Consider a multi-step transactional process like booking a flight ticket. SOAP’s stateful capabilities can help maintain the session throughout the booking process, ensuring that user data is consistently available across multiple requests.

If you’re building a content management system where each HTTP request is independent and doesn’t rely on previous requests, REST’s stateless nature simplifies both server and client interactions, making it suitable for systems where maintaining session states isn’t a primary concern.

Error Handling: Built-in vs. Dependent on Implementation

SOAP comes with built-in error handling through standardized fault messages, making it easier to pinpoint issues. In REST, error handling is dependent on the implementation, often utilizing HTTP status codes. This flexibility can be both a blessing and a curse.

When developing a healthcare information exchange system, the built-in error handling of SOAP, with standardized fault messages, ensures that any errors in transmitting critical patient data are immediately and clearly addressed, enhancing patient safety.

In the context of a public-facing news website, REST’s flexibility in error handling allows you to tailor error responses to suit the specific needs of various clients. While this flexibility can be advantageous, it also requires a more meticulous hand in implementation.

Security: WS-Security vs. Dependent on Protocols like HTTPS

SOAP provides robust security features through WS-Security, making it an excellent choice for sensitive data and regulated industries. REST relies on the underlying transport protocol, such as HTTPS, for security, which is suitable for most use cases.

A banking application that deals with sensitive financial transactions would benefit from SOAP’s WS-Security’s strong encryption and authentication, ensuring that customer data is protected to the highest standards and complies with regulatory requirements.

However, for a weather forecast service that provides publicly available information, relying on the underlying transport protocol’s security, such as HTTPS, is a cost-effective and suitable choice. This minimizes the complexity of security implementation for non-sensitive data.

These distinct capabilities and features illustrate how the choice between SOAP vs. REST is as complex as the specific requirements and constraints of your project. Your choice should align with the goals, resources, and nature of your business.

Factors to Consider When Choosing Between SOAP vs. REST

When standing at the crossroads of API design decisions, i.e., SOAP vs. REST, several critical factors come into play. Your choice between SOAP and REST isn’t just a technical matter; it’s a strategic decision that impacts your project’s success. Here are some key factors to keep in mind:

Nature of the Project

It’s all about matching your API to your project. For example, if you’re building a big enterprise system with lots of complex processes that need to be just right, SOAP is a good pick. It’s the sturdy, reliable option. But if you’re creating a dynamic public web app or working on smaller connections, REST is a more flexible option.

Required Level of Security

From a data security POV, keep in mind that if your API handles processes with confidential data assets like financial transactions or personal medical records, SOAP has stronger security features that’ll keep your data safe. For non-sensitive data, REST is both more cost effective and has enough security.

Expected Volume of Traffic and Scalability Needs

If you’re expecting a huge crowd and loads of data, REST is the go-to choice. It’s good at handling a lot of requests without getting bogged down. But if you need to keep meticulous access records, SOAP’s is the better choice.

Integration with Existing Systems

Another important factor is how your new API fits in with your current systems. If your organization already uses mostly SOAP-based services, a SOAP-based API will make your life easier and vice versa with REST-based services.

The Skillset of the Development Team

If your development team is skilled with XML and structured data, SOAP aligns well with their existing skill set. If their expertise leans toward web technologies, REST is quicker and easier. A solution that works irrespective of technical skill is a no-code API development solution.

Conclusion

Your decision when evaluating SOAP vs. REST should be driven by your unique business needs, technical demands, and future aspirations. There’s no one-size-fits-all answer, and that’s perfectly okay. SOAP and REST are like different tools in a toolbox, each designed for specific tasks. So, whether you opt for SOAP or REST, it’s all about crafting an API that perfectly fits your mission, ensuring that your digital endeavors are primed for success.

Contact us to learn more about how Astera, a self-service no-code API design tool, can support your API strategy.