Decoding API Architectures: SOAP vs. REST

The differences between SOAP and REST APIs will be discussed in this post.

We will give a general outline of what an API involves and its functional utility before diving into this discussion.

What Qualifies as an API?

A software interface known as an application programming interface (API) enables easy communication between various applications. An API is essentially a collection of programs that consumers can call and run. In simpler terms, it makes it possible for one application to use a specific interface to access the data of another application.

What-Qualifies-as-an-API

Understanding the Mechanism of APIs

Let’s think about a practical example to better understand how API functionality works. Think about going to a restaurant to eat. Your order is taken by the waiter, who then relays it to the kitchen service. After that, the kitchen prepares your ordered food and serves it to you.

In this imagined scenario, the kitchen represents our database, from which data is retrieved and displayed, and the waiter acts as a metaphor for an API.

What is SOAP?

The Simple Object Access Protocol, or SOAP, was created before REST. The primary idea behind SOAP is the ability of applications to work together across several platforms, facilitating effective data interchange. The strong security features of SOAP APIs are one of the main drivers behind using them to create applications.

What is REST?

A type of web service is REST, or Representational State Transfer. REST APIs follow HTTP protocols and function based on URLs. They use the JSON data format and are also frequently referred to as restful Web Services. By allowing client-server interactions within architectural paradigms, REST accomplishes its goals.

It works based on client-server communications and architectures.

What is the Difference Between REST and SOAP APIs?

SOAP and REST are two methods of exchanging data over the Internet. Consider the scenario where data is shared between your internal accounting system and the accounting system of your client to automate billing operations. Using an API that establishes communication guidelines, the two programs share data.

There are two different methods for designing APIs: SOAP and REST.

The SOAP technique uses an XML data format and is quite organized. Because REST is more versatile, apps can exchange data in a variety of formats.

What Connections do SOAP and REST have?

You can use a wide range of programming languages, architectures, and platforms to create applications. Because the data formats used by these many systems vary, sharing data between them might be difficult. To address this issue, SOAP and REST were both developed.

To create APIs or connection points between several applications, SOAP and REST can be used. Web service and API are phrases that are frequently used synonymously. APIs are the more inclusive category, though. A specific class of API is called web services.

Here are other similarities between SOAP and REST:

  • They both outline guidelines and expectations for how applications should create, handle, and respond to requests for data from other applications.
  • They both communicate using HTTP, a widely used internet protocol.
  • Both of them support SSL/TLS for safe and secure communication.
  • To create secure, scalable, and fault-tolerant distributed systems, you can utilize either SOAP or REST.

SOAP vs. REST Example

1. SOAP Example:

Using the SOAP API, build up the XML request with the body. The request body contains an envelope, which is a type of SOAP wrapper that identifies your API request. The SOAP request body has request parameters.

In this case, we want to fetch the student with the name “John”. So based on the below screenshot, our request is built and sent to the API.

Also Read: How to Create SOAP Web Service Using WSDL in ASP.NET Core

SOAP Message Structure:

Diagram of a SOAP message structure showcasing an envelope that includes a header block and a fault in the body, juxtaposing SOAP with elements distinct from REST protocols.

Request

A snippet of SOAP XML code with a tag for "Student Details Request" includes a sub-tag with the name "John," showcasing the intricacies unique to SOAP and distinct from REST.

The API then provides information on “John” the student, in the form of an XML body response.

Response 

Response

2. REST Example:

HTTP URLs are used to gain access to the REST API. The URL must contain parameters if it is to be processed as a GET request.

GET https://restexample.com/students?name=John

The JSON data format is used by the REST API to return Student Details related to the name “John”

In a seamless blend of RESTful style, the JSON data reveals three fields: "name" with the value "John," "age" set at 30, and "address" listed as "California. - Rest API

Another Example of Rest is here,

Diagram explaining REST API interaction: Client sends HTTP requests (GET, POST, DELETE, PUT) to a server URL. Unlike SOAP, the server responds with JSON data.

In this example, the client is a web application. REST APIs can be consumed by a broad range of clients, like

  • Web Browsers
  • Mobile applications
  • Desktop applications
  • IOTs, i.e., the Internet Of Things

HTTP verbs play a very important role in the Restful Web API. The most common HTTP verbs are GET, PUT, POST, and DELETE, which correspond to CRUD (Create, Read, Update, and Delete) operations, respectively.

  • GET
  • POST
  • PUT
  • PATCH
  • DELETE

Here we have displayed the HTTP verb’s operation mode in the visual image.

Further Read: Combine ASP.NET Identity Web API and MVC Best in a Single Web App

Table illustrating how HTTP verbs align with CRUD operations in REST and SOAP: Post corresponds to Create, Get aligns with Read, Put or Patch signifies Update, and Delete matches Delete.

Difference between SOAP and REST

SOAPREST
MeaningSimple Object Access ProtocolRepresentational State Transfer
DesignStandard Protocol with predefined rules to followArchitectural Style with loose recommendations and guidelines
ApproachFunction DrivenData Driven
SatefulnessStateless by default but a SOAP API can be made statefulStateless in nature; there is no server-side session.
CachingAPI calls are not cachedAPI calls are cached
SecurityWS-Security with SSL Support. Provides in-built ACID complianceSupport HTTPS and SSL.
PerformanceRequires more power, resources, and bandwidthRequires fewer resources.
Messaging FormatXML OnlyXML, JSON, Plain Text, YAML, HTML, and Others
Transfer ProtocolSMTP, HTTP, UDP, and othersHTTP Only
NatureHeavy WeightLight Weight
Recommended forFinancial services, enterprise-level apps, payment gateways, high-security apps, and telecommunication servicesPublic APIs for web services, social networks, and mobile services
AdvantagesStandardization, security, and extensibilityHigh Performance, Scalability, Flexibility, and browser friendliness
DisadvantagesMore complex, poor performance, and less flexibilityUnsuitable for distributed environments; less security

In conclusion,

The comparison between SOAP and REST APIs revolves around choosing the right tool for specific application needs. SOAP, with its structured XML format and robust security features, suits complex enterprise-level applications, financial services, and high-security systems.

However, it’s resource-intensive and less flexible. On the other hand, REST, with its lightweight, data-driven approach using HTTP and various data formats like JSON, is an excellent choice for public APIs, web services, and mobile applications. It offers high performance, scalability, and flexibility, making it a favorite for distributed environments.

Also, both SOAP and REST can be used to create custom API Integration services that allow different applications to communicate and share data effectively. The choice between SOAP and REST depends on factors like the specific requirements of the integration, the existing technology stack, and the desired level of flexibility and complexity.

Should you require any further refinements or clarifications, please do not hesitate to contact us.
Article by

Chintan Prajapati

Chintan Prajapati, a seasoned computer engineer with over 20 years in the software industry, is the Founder and CEO of Satva Solutions. His expertise lies in Accounting & ERP Integrations, RPA, and developing technology solutions around leading ERP and accounting software, focusing on using Responsible AI and ML in fintech solutions. Chintan holds a BE in Computer Engineering and is a Microsoft Certified Professional, Microsoft Certified Technology Specialist, Certified Azure Solution Developer, Certified Intuit Developer, and Xero Developer.Throughout his career, Chintan has significantly impacted the accounting industry by consulting and delivering integrations and automation solutions that have saved thousands of man-hours. He aims to provide readers with insightful, practical advice on leveraging technology for business efficiency.Outside of his professional work, Chintan enjoys trekking and bird-watching. Guided by the philosophy, "Deliver the highest value to clients". Chintan continues to drive innovation and excellence in digital transformation strategies from his base in Ahmedabad, India.