Which permission is necessary for a user to access the SOAP API?

To access the SOAP API in Salesforce, the necessary permission is the "API Enabled" permission. This permission grants users the ability to utilize APIs, which includes the SOAP API, for data manipulation and retrieval operations. Without this permission, users would be unable to establish a connection with Salesforce through the SOAP API and perform any actions such as querying or updating records programmatically.

The "API Enabled" permission is a specific permission that can be assigned to profiles or permission sets, allowing for precise control over which users have the ability to work with APIs. It is foundational for any integration efforts, as it sets the stage for secure and proper API usage.

Other options like "API Access," "System Administrator," and "Full Access" do not specifically pertain to the required permission for SOAP API access. "API Access" is not an official Salesforce terminology for permissions, and while a System Administrator typically has the API Enabled permission, it is not a prerequisite for accessing the SOAP API specifically. Full Access refers to a broader level of access that includes many other functionalities beyond just API access, and hence does not pinpoint the necessary API permission uniquely needed for SOAP.