Which of the following is NOT a characteristic of the Composite API?

The Composite API is designed to enhance efficiency when interacting with Salesforce by allowing multiple operations to be combined into a single API call, thereby improving performance and optimizing resource usage. One of its key features is that it can integrate various API functions, allowing for batch processing of operations across different objects or functions. By reducing the number of separate API calls needed, it minimizes the overhead involved in making multiple requests, which leads to faster response times.

The assertion that the Composite API is only applicable to SOAP APIs is incorrect, as the Composite API is actually designed to work with REST APIs, making it more versatile. It supports both REST and SOAP in its context but is primarily utilized within RESTful applications to optimize performance and resource management. Therefore, identifying this characteristic as "not" belonging to the Composite API is valid, as it significantly narrows its applicability.