REST vs. SOAP APIs

Understanding REST vs SOAP

A RESTful approach is the better option for applications that require CRUD operations (create, read, update, and delete). A good example is a content management system (CMS), which uses standard HTTP methods—POST, GET, PUT, and DELETE—to create and maintain entities. Additionally, REST’s ability to cache responses makes it a good fit for high-demand applications where certain requests are made frequently. Finally, REST is very popular, and companies that use a RESTful design for public APIs are able to cater to a wider range of developers who have dealt with REST before.

On the other hand, systems that have strict API security requirements and regulations may benefit from a SOAP-based approach because of its built-in security measures. For instance, its support for WS-Security and strongly-typed contracts makes SOAP a better fit for systems that send and receive highly sensitive data, such as financial and healthcare information.

Benefits of REST APIs

Related: What is a REST API?

Designing scalable and maintainable web services can be difficult, which is where REST comes in handy. REST is an architectural style that provides a set of guidelines, conventions, and best practices for developing well-designed networked applications.

APIs that are designed according to REST principles are referred to as “RESTful APIs,” and they have the following features in common:

• Statelessness: The server should not need to store any information about the client’s state. Rather than storing session information, a client should provide all the necessary details in its request.

• Separation of concerns: The client and server should be properly decoupled from each other, which allows each one to evolve independently.

• Layered architecture: Software architecture should be split into layers with their own distinct purpose, which helps keep the system modular and maintainable.

• Cache support: Responses can be cached on the client to improve an application’s performance and remove the need to re-process repeated requests.

• Consistent interface: HTTP methods like GET, POST, and DELETE help make interactions between clients and servers simple and consistent.

• Emphasis on resources: RESTful APIs are resource-based, rather than method-based or function-based. A resource can be an object, entity, or data within a system. Resources are uniquely identified using a Uniform Resource Identifier (URI), and HTTP methods are used to perform CRUD operations (create, read, update, delete) on them.

• Support for standard media types: Resources are represented using standard media types, such as JSON, XML, or plain text. Clients can request that servers deliver a response in their preferred media type.

Advantages and disadvantages of REST APIs

An overview of the pros and cons of REST APIs.

 

Advantages	Disadvantages
Scalability	Incompatibility with real-time functionality
Universal conventions	Significant overhead with binary data transfer
Interoperability	Reliance on HTTP
Improved performance

Advantages of REST

REST provides a straightforward approach to seamless communication between clients and servers. Following the basic principles of this architectural style can lead to a variety of benefits, including:

• Scalability: The stateless nature of REST APIs means that the session state does not need to be shared or synchronized across various instances, which makes horizontal scaling easier. As a result, you can add additional servers during peak traffic without any disruption to functionality or risk of losing any important session state.

• Universal conventions: Applications that follow standardized, universal conventions provide a much better developer experience and improve the system’s maintainability. Having a consistent interface also improves interoperability and makes it easier for various systems to communicate with one another.

• Interoperability: Any client that supports HTTP can use a RESTful API, regardless of its platform or programming language.

• Improved performance: Latency and server load can be drastically reduced by caching server responses. This leads to better performance and user experience, as well as cost savings from minimized computational overhead.

Disadvantages of REST

Although REST is the most popular approach for designing APIs, it is not without drawbacks. An in-depth understanding of the potential disadvantages associated with a RESTful API will help you determine whether this approach meets your application’s needs. Here are some challenges of REST that should be taken into consideration:

• Incompatibility with real-time functionality: RESTful APIs are not the ideal fit for applications that require live data due to their request-response-based approach. In a request-response model, the client must send a request to the server and wait for the server’s response, which is inherently inefficient for real-time applications.

• Significant overhead with binary data transfer: When large binary files, like images or videos, are sent via a RESTful API, they must be encoded and decoded. This overhead can cause an increase in bandwidth consumption and slower transfers, which introduces a risk of timeouts. An alternative protocol and design would be better suited for this use case.

• Reliance on HTTP: REST was designed with HTTP in mind, which is why it is typically implemented using HTTP. Its natural alignment with HTTP may restrict the range of devices to which a RESTful API can cater.

Although REST is a highly popular approach for web service communication, it is important to recognize that there are other options available. One alternative is Simple Object Access Protocol, also known as SOAP.

Benefits of SOAP APIs

Related: What is a SOAP API?

Simple Object Access Protocol (SOAP) is a protocol for exchanging information between systems over the Internet, using XML as its message format. Unlike REST, SOAP follows a very strict structure. It uses standardized contracts such as Web Service Definition Language (WSDL) to specify the functionalities of an API.

Advantages and disadvantages of SOAP APIs

An overview of the pros and cons of SOAP APIs.

 

Advantages	Disadvantages
Extensibility	Less performant
Support for many protocols	Complex
Strong typing	Less intuitive
Standardized error handling
Heightened security

Advantages of SOAP

Despite its waning popularity, SOAP offers some benefits that REST does not, such as:

• Extensibility: Developers can extend and add functionality as needed by using XML namespaces and custom header elements.

• Support for many protocols: Unlike REST, which is more commonly used with the HTTP protocol, SOAP can be used with a wide range of protocols such as HTTP, SMPT, and even specialized protocols like Microsoft Message Queuing (MSMQ).

• Strong typing: The XML schema is used to define the structure of messages and their data types. This helps improve data validation, detect errors, and reduce the potential for communication errors.

• Standardized error handling: SOAP uses a fault element to communicate errors that occur during message processing. A standardized approach to error handling allows different systems to parse and handle errors in a consistent manner.

• Heightened security: SOAP has built-in security standards, such as WS-Security, that ensure messages can be sent and received securely. It also supports security measures such as digital signatures, tokens, and encryption to ensure the integrity and confidentiality of messages.

Disadvantages of SOAP

SOAP has numerous benefits, but it also has its own unique set of disadvantages. For instance, SOAP APIs are:

• Less performant: SOAP messages can be quite large due to their verbose XML-based structure, which can lead to greater bandwidth usage and slower performance.

• Complex: SOAP can introduce complexity into a system due to its strongly typed and extensible nature. REST offers a far simpler approach.

• Less intuitive: SOAP is centered around actions and methods, which many find less intuitive than REST’s resource-based approach.

REST vs SOAP FAQs

 

Question	Answer
What’s the main difference between SOAP and REST?	REST is an architectural style, while SOAP is a protocol. REST uses simple HTTP methods for CRUD operations and is widely adopted for its flexibility and performance. In contrast, SOAP provides built-in security features and strict contracts, making it better suited for highly regulated industries such as finance and healthcare.
What does REST stand for?	Representational State Transfer
What does SOAP stand for?	Simple Object Access Protocol
When to use REST?	Modern web apps, public APIs, and microservices.
When to use SOAP?	Enterprise systems, financial transactions, and high security.
REST vs SOAP: Which is more flexible?	REST is more flexible than SOAP. REST has a simpler architecture and supports multiple data formats, including JSON and HTML, while SOAP is rigid and only supports XML.
SOAP vs REST: Which is faster?	REST is faster because it uses smaller message sizes. Plus, REST responses are cacheable, enabling the server to store frequently accessed data, which in turn results in faster page load times. OLD

The bottom line

Related: Use the REST API Basics Template

REST and SOAP both have unique benefits and drawbacks that affect their suitability for various use cases.

Software development often involves choosing between several possible solutions, which is why it’s important to understand the advantages and disadvantages of the available options. REST and SOAP approach API development very differently, which creates a clear distinction between the use cases for which each is suited. By carefully considering the application’s objective, developers will be able to make an informed decision on which approach will provide the best end-user experience.