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Comparing SOAP and REST APIs

Introduction

When it comes to web service architectures, SOAP (Simple Object Access Protocol) and REST (Representational State Transfer) stand out as two prominent choices, each with its own set of characteristics, use cases, and design philosophies. In this article, we’ll explore the main differences between SOAP and REST APIs, their usages, and provide examples for better understanding.

Key Differences

1. Protocol:

• SOAP: A protocol-heavy standard that relies on XML as its message format. It typically uses HTTP, SMTP, or other protocols for message transmission.
• REST: An architectural style based on a set of constraints, utilizing various protocols like HTTP, HTTPS, and others. REST commonly communicates using JSON or XML for data interchange.

2. Message Format:

• SOAP: Employs XML as its message format, offering a standardized structure with a well-defined schema.
• REST: Allows flexibility in choosing the message format, with JSON being the most popular due to its lightweight and human-readable nature.

3. Statefulness:

• SOAP: Generally considered stateful, meaning the server retains information about the client’s state between requests.
• REST: Stateless by design, each request from a client contains all the information needed for the server to fulfill it, eliminating the need to store client state on the server.

4. Flexibility:

• SOAP: Strict standards and a predefined contract between the client and server, making it more rigid but ensuring a high level of reliability.
• REST: Embraces a more flexible approach, allowing developers to choose the design patterns that best fit their application requirements.

Usages

SOAP

• Enterprise-Level Integration: Commonly used in large-scale enterprise applications where a strict and standardized communication protocol is necessary.
• Complex Transactions: Suitable for scenarios requiring ACID-compliant transactions and comprehensive error handling.

REST

• Web and Mobile Applications: Widely adopted for web and mobile applications due to its simplicity, scalability, and ease of integration.
• Stateless Services: Ideal for services that don’t require the server to retain information about the client’s state between requests.

Examples

1. SOAP

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" 
                  xmlns:web="http://www.example.com/webservice">
   <soapenv:Header/>
   <soapenv:Body>
      <web:GetUserInfo>
         <web:UserID>123</web:UserID>
      </web:GetUserInfo>
   </soapenv:Body>
</soapenv:Envelope>

2. REST

GET /users/123

In the SOAP example, the request is wrapped in an XML envelope with a specific structure, whereas the REST example uses a simple HTTP GET request with the user ID as part of the URL.

Hope you learned something new.❤️

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