Which of the following APIs is not part of the key Salesforce data APIs?

The GraphQL API is not considered one of the key Salesforce data APIs. Salesforce primarily emphasizes the REST API, SOAP API, and Bulk API as foundational tools for interacting with its data services.

The REST API is widely used for web-based applications, allowing easy data access with a simple HTTP interface, making it ideal for mobile and web applications. The SOAP API is well-suited for integrations that require a strict contract between systems, often employed in enterprise-level applications for its robustness and support for complex transactions. The Bulk API, on the other hand, is optimized for loading and manipulating large volumes of data efficiently, which is crucial for data migrations and batch processing.

While GraphQL is a popular and evolving API technology gaining traction in various platforms for its flexible querying capabilities, as of the last update, it is not a core part of Salesforce's official suite of data APIs. This distinction highlights the focus of Salesforce on REST, SOAP, and Bulk APIs as the primary means for data integration and manipulation.