Guide to Amazon API Gateway Caching

API Gateway Caching is a powerful feature provided by AWS to improve the performance of your APIs and save backend systems from heavy loads.

What is API Gateway Caching?
It works by storing responses from your backend systems and reusing them for a period, instead of forwarding every request to your backend services. This is especially useful to prevent overloading of your services and improve latency.

Why it is important?
With caching, you reduce the amount of requests to your backend services, which can significantly reduce the costs of running your applications. Moreover, cached responses are returned faster, which improves the user experience.

How does it work?
When a request is made, API Gateway checks if a valid cached response is available. If so, it returns the cached response, otherwise it forwards the request to the backend and caches the response for future use.

Exam Tips: Answering Questions on API Gateway Caching
1. Understand how caching works and its benefits.
2. Be aware that caching can reduce costs and improve performance.
3. Keep in mind that cache settings can be customized, including encryption, TTL (Time to Live) and capacity.
4. Understand that not all responses are cacheable; AWS uses standard HTTP protocols to determine cacheability.
5. Remember that you may need to clear the cache manually if your backend responses change and should be refreshed immediately.
6. Note that caching in API Gateway is different from CloudFront caching, and both can be used together.