Which capabilities of Salesforce outbound messaging are correct?

The correct statement regarding Salesforce outbound messaging is that outbound messaging does not provide a session ID as part of the outbound message. Instead, it typically sends a message to a listener endpoint in a SOAP format, which does not inherently include a session ID. This approach is designed for stateless integrations, allowing for better scalability and reliability.

The second statement about repeatedly sending a SOAP notification for up to 24 hours until an acknowledgment is received is an important characteristic of outbound messaging. Salesforce will attempt to resend notifications that have not been successfully acknowledged by the receiving endpoint, up to a maximum of 24 hours.

The third option highlights that Salesforce outbound messaging allows for integration components to be built without APEX, which is correct. Outbound messaging can directly use workflow rules or process builder, enabling setup without requiring custom code.

The final choice regarding defining a WSDL based on two related objects is not accurate. While WSDLs can be used for API integrations, outbound messaging typically does not automatically generate a WSDL based on object relationships, particularly in the context of Master-Detail relationships.

Understanding these capabilities helps in designing effective integrations using Salesforce's outbound messaging feature.