Salesforce Certified Identity and Access Management Practice

The primary purpose of the API session ID and endpoint URL in external application authentication is to represent users in API requests.

When external applications interact with Salesforce via its APIs, they must securely authenticate and identify which user is making the request. The API session ID acts as a token that is generated upon successful authentication, and it uniquely associates the request with a specific user’s session. This enables the external application to make authorized API calls on behalf of the user, ensuring that the request is performed within the context of that user's permissions.

In this context, other options do not directly align with the primary function of the API session ID and endpoint URL. For instance, while user credentials must indeed be verified during the initial authentication process, this verification is done before obtaining the API session ID. Similarly, encrypting user data is not the primary role of the session ID, and accessing Visualforce pages does not directly pertain to the purpose of authentication in external applications. Thus, the representation of users in API requests is the most accurate description of the role played by the API session ID and endpoint URL.