DVA-C02 Development with AWS Services Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Enable caching in the Lambda function code

  Why it's wrong here

  This option is incorrect because API Gateway's built-in caching mechanism operates at the API layer, external to the Lambda function's execution environment. While a Lambda function *could* implement its own application-level caching using services like ElastiCache, the question implies leveraging API Gateway's native caching to reduce latency for API responses. Enabling caching within the Lambda function code would not utilize API Gateway's integrated caching feature, which is designed to intercept and serve responses before invoking the backend.

• ✗

  Set the TTL in the API Gateway method request integration

  Why it's wrong here

  This option is incorrect because the Time-To-Live (TTL) for API Gateway's stage-level caching is configured within the cache settings for a specific stage, not directly within the method request integration settings. The method request integration primarily defines how API Gateway maps incoming request parameters to the backend integration, such as a Lambda function. Cache settings, including TTL, cache capacity, and encryption, are distinct configurations applied to the API Gateway stage itself after caching has been enabled.

• ✓

  Create a cache cluster in API Gateway for the stage

  Why this is correct

  This is the correct approach for reducing latency by caching API responses directly within API Gateway. To enable caching, a cache cluster must be provisioned and associated with a specific API Gateway stage, where you define its capacity (e.g., 0.5 GB to 237 GB) and the default Time-To-Live (TTL) for cached responses. Once enabled, API Gateway intercepts requests, serves cached responses if available and valid, and only invokes the backend Lambda function when a cache miss occurs or the cache entry expires.

• ✗

  Use Amazon ElastiCache and modify the Lambda function to check cache

  Why it's wrong here

  Using Amazon ElastiCache requires the Lambda function to implement cache-check logic itself, whereas API Gateway caching operates at the API layer without code changes. This option is tempting because ElastiCache is a valid caching service for reducing latency in Lambda-based applications, and it would be correct if the requirement were to cache database query results or session data rather than API responses.