Which method is used for real-time data updates between Salesforce and an external system?

The method that facilitates real-time data updates between Salesforce and an external system is remote call-in integration using web-services. This approach utilizes various web service protocols, such as REST or SOAP, to establish a direct connection between Salesforce and external systems. With this integration, Salesforce can send or receive data instantly as events occur, ensuring that both systems are synchronized and that users have access to the most current information.

In contrast, batch data synchronization focuses on processing and transferring data in groups at scheduled intervals, which does not support real-time updates. Asynchronous data updates are designed for operations that can occur without immediate results, where responses may not be required immediately, thus lacking the immediacy of real-time synchronization. Scheduled data import involves periodic updates at fixed times, again not enabling the instant data transfer required for real-time operations.

Overall, remote call-in integration using web-services is the ideal solution for scenarios that demand immediate interaction and up-to-date information between Salesforce and external systems.