What is SOAP, how does it differ from REST, and where is it used?

SOAP (Simple Object Access Protocol) is a protocol for exchanging structured messages in distributed systems, based on XML. It defines a strict message format, uses WSDL to describe services, and supports advanced features such as security, transactions, and reliable delivery.

Differences between SOAP and REST:

• Protocol vs architectural style: SOAP is a protocol with strict standards, REST is an architectural style that uses HTTP and simple formats (JSON, XML).
• Message format: SOAP uses XML with a defined structure, REST can use various formats, most commonly JSON.
• Complexity: SOAP is more complex to implement and requires more resources, REST is simpler and lighter.
• Standards: SOAP supports security standards (WS-Security), transactions, and reliable delivery.

Where SOAP is used:

• In enterprise systems where strict typing and advanced features are important (e.g., banking systems, telecommunications).
• Where guaranteed message delivery and security are required.

REST is more often used in web applications and mobile services due to its simplicity and ease of integration.