What makes RESTful web services different from SOAP?

RESTful web services and SOAP represent two distinct approaches for designing web services, each with unique characteristics. REST: Pros: Simplicity, Lightweight, Flexibility, Scalability. Cons: Limited Standardization, Security considerations. SOAP: Pros: Standardization, Security, Transaction support. Cons: Complexity, Overhead, Stateful nature. Use Cases RESTful web services are a good for applications that need to be easy to use, scalable, and interoperable. They are also a good choice for applications that need to be able to handle a high volume of traffic. SOAP is a good choice for applications that need to be secure and transaction-oriented.

RESTful: Based on HTTP, simple and stateless, uses flexible formats like JSON, suitable for web and mobile apps with lower overhead. SOAP: Uses XML, operates over various protocols, can be stateful, rigid with XML structure, common in the enterprise, and may have higher overhead.

RESTful web services and SOAP differ in architecture, message format, transport, state, methods, and more. REST is an architectural style, using lightweight formats like JSON or XML, typically over HTTP, and is stateless. It uses standard HTTP methods, making it simple and flexible, often used for public APIs and web apps. SOAP, on the other hand, is a protocol that uses XML, supports various transport protocols, and can be stateful. It defines custom operations in a WSDL file, offering rigidity and built-in security features. The choice between them depends on the project's needs and complexity.

RESTful web services and SOAP are two different approaches to designing web services. RESTful web services are based on the Representational State Transfer (REST) architectural style, while SOAP is a protocol that defines how to exchange XML messages between web services.

RESTful, or Representational State Transfer, is an architectural style for designing networked applications. It operates over the standard HTTP protocol and is based on a set of principles that emphasize a stateless client-server interaction. RESTful web services use standard HTTP methods (GET, POST, PUT, DELETE) for communication and commonly rely on JSON or XML for data representation.

I usually consider SOAP a highly-formalized evolution of XML-RPC, allowing for much more complexity and flexibility in terms of authentication and request/response object formats. The XML document that describes the service, called the WSDL, being part of the specification allows for automated generation and validation of the client and server sides of the API without additional tooling or descriptive documentation. This makes it particularly well-suited to waterfall-style SDLCs where the entire API will be designed out before anyone begins implementing. However this extremely formality has caused it to fall out of favor as companies adopt more agile methods and lean on lighter RESTful services.

As per my experience, Simple Object Access Protocol(SOAP) is a protocol for exchanging structured information in web services. Unlike REST, SOAP is a protocol, not an architectural style, and it operates over various protocols, including HTTP, SMTP, and more. SOAP messages are typically XML-based and are used to enable communication between applications over a network. SOAP relies on a set of well-defined standards for messaging, such as XML Schema for message structure and Web Services Description Language (WSDL) for describing the functionalities offered by a web service.

SOAP, in contrast to REST, offers a robust set of standards that contribute to enhanced security and integrity in communication between applications. The strict standards in SOAP protocols ensure a high level of consistency and reliability, making it particularly suitable for enterprise-level applications. One notable advantage is the built-in error handling mechanism, which follows standardized procedures for detecting and resolving issues during communication. SOAP also supports stateful operations, allowing for the maintenance of session information between requests.

Since RESTfulness is more a design philosophy than a strict specification API design is often less clear-cut. REST APIs also tend to require additional documentation and tooling like SwaggerSpec/OpenAPI and Pact or other form of contract to enable automated implementation validation and client code generation. REST itself also has no opinions on how things like pagination or object versioning should be done, leading to a lack of consistency in implementations. Additional metadata constraints like HAL/HATEOAS/JSON-LD haven't really caught on and aren't opinionated enough to provide standard solutions.

When discussing the differences between RESTful web services and SOAP, it is important to consider the broader context and implications of each technology. The choice between RESTful and SOAP should be guided not just by their technical differences but also by considerations like integration capabilities, developer expertise, performance needs, and future industry trends.

RESTful services utilize the simplicity of HTTP, which is well-suited for web and mobile applications. In contrast, SOAP can operate over a variety of protocols, offering greater flexibility but potentially introducing more complexity. RESTful commonly using JSON for its lightweight and human-readable nature, while SOAP relies on XML, which can be more verbose. RESTful is popular in scenarios where simplicity and scalability are prioritized, such as in modern web development. On the other hand, SOAP is often chosen for enterprise-level applications where adherence to strict standards, security, and transactional consistency are paramount.