SOAP (Simple Object Access Protocol)

• Protocol: A strict communication protocol.
• Format:Always XML (SOAP messages are wrapped inside an ).
• Transport: Usually HTTP, but can also use SMTP, TCP, etc.
• Standards: Has built-in rules for security (WS-Security), transactions, error handling.
• State: Stateful or Stateless.
• Tight coupling: Requires both client and server to strictly follow WSDL (Web Services Description Language).

REST (Representational State Transfer)

• Architecture style (not a protocol).
• Format: Can use JSON, XML, HTML, or plain text (JSON is most common).
• Transport: Always uses HTTP (GET, POST, PUT, DELETE).
• Stateless: Each request contains all necessary info (server doesn’t remember client state).
• Lightweight & flexible compared to SOAP.