A Detailed Overview of AWS API Gateway

Look inside the black box of AWS API Gateway to understand authorization, method requests and responses, integration requests and responses, VTL templates, and more. AWS API Gateway is an awesome service to use as an HTTP frontend. You can use it for building serverless applications, for integrating with legacy applications, or for proxying HTTP requests directly to other AWS services.

But understanding the elements of API Gateway can be difficult. If you’re like me, your understanding of API Gateway might be like the following: The most important element is the integration. I’ll sometimes refer to it as a “backing integration” as well.

This is the raison d’etre of the API request — what the client is actually trying to do. It is outside of API Gateway itself. The integration is where API Gateway will route your request once it passes authorization and validation.

An integration could be a Lambda function that processes a payload. It could be an HTTP endpoint which is forwarded the request. It can even be another AWS service that is called directly by API Gateway.

The two other main elements in API Gateway are the request and the response flows. The request flow contains everything before the HTTP request hits the backing integration and is concerned with validating and preparing your request for your integration.

Source: alexdebrie.com