What is SOAP and how does it differ from RESTful web services?

SOAP (Simple Object Access Protocol) is a protocol used for exchanging structured information in web services. It relies on XML for message format and typically uses HTTP or SMTP as the transport protocol. SOAP is known for its strict message structure and well-defined processing rules.

On the other hand, RESTful web services use Representational State Transfer (REST) architecture to communicate over the web. RESTful services utilize standard HTTP methods (GET, POST, PUT, DELETE) for data manipulation and typically operate over lightweight data formats such as JSON or XML.

One of the key differences between SOAP and RESTful web services is their architectural styles. SOAP is more rigid and relies on a predefined contract, while REST is more flexible and follows principles such as statelessness and resource-based interactions.

In terms of communication protocols, SOAP typically uses XML for message format and WSDL (Web Services Description Language) for service description, while RESTful services rely on using URLs to access resources directly.

Overall, the choice between SOAP and RESTful web services depends on the specific requirements of the application, with SOAP being more suitable for enterprise-level systems that require strict message formatting and detailed service contracts, while REST is often preferred for simpler, lightweight APIs that prioritize simplicity and scalability.