What is the primary function of an API gateway in MDC3?

• A. It is a database replication tool.
• B. It logs errors but does not manage APIs.
• C. An API gateway handles routing, authentication, rate limiting, caching, and protocol translation; central to MDC3 API management.
• D. It is a user authentication service only.

Answer: (C)

An API gateway serves as the single entry point for API clients and manages how API requests are handled across the system. It routes requests to the correct backend services, enforces authentication and authorization, applies rate limiting to protect services from abuse, can cache responses to improve performance, and handles protocol or data-format translation as needed. This combination is what enables centralized, consistent API management in MDC3, making it the primary function.

Other options miss this broader orchestration: a database replication tool focuses on data synchronization, not API traffic; logging errors without managing APIs leaves traffic and security concerns unaddressed; a user authentication service handles identity but not routing, rate limiting, or protocol translation.