Practice Test Geeks(CSI) Certified System Integrator Practice Test
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RESTful API & Middleware Design Flashcards

7 cards from real CSI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 RESTful API & Middleware Design flashcards as text

  1. In a microservices architecture, what is the main advantage of using an API gateway over direct service-to-client communication?

    Answer: It provides a single entry point for cross-cutting concerns like rate limiting and auth

    An API gateway centralizes cross-cutting concerns so individual microservices don't each need to implement them separately.

  2. What distinguishes a 'stateless' REST API interaction from a stateful one?

    Answer: Each request contains all information needed for the server to fulfill it without session context

    REST statelessness means each request is self-contained; the server maintains no client session state between calls.

  3. Which OAuth 2.0 grant type is most appropriate for a server-to-server REST API integration with no user involvement?

    Answer: Client Credentials

    Client Credentials grant is designed for machine-to-machine authentication where no user context is required.

  4. A system integrator needs to ensure that duplicate API requests (due to network retries) don't cause duplicate side effects. Which technique addresses this?

    Answer: Implementing idempotency keys on non-idempotent endpoints

    Idempotency keys allow servers to detect and deduplicate retried requests, returning the original result without re-processing.

  5. In REST API design, what is the correct HTTP method and response code for successfully creating a new resource?

    Answer: POST returning 201 Created

    POST is used to create resources, and 201 Created with a Location header pointing to the new resource is the standard response.

  6. Which middleware pattern is best suited to aggregate responses from multiple microservice calls into a single API response?

    Answer: Backend for Frontend (BFF) pattern

    The BFF pattern creates a dedicated backend layer per frontend type that aggregates and tailors data from multiple downstream services.

  7. What is the purpose of the CORS preflight OPTIONS request in REST API communication?

    Answer: To ask the server if the actual cross-origin request is permitted

    Browsers send a preflight OPTIONS request to verify the server allows the actual cross-origin request's method and headers.