https://medium.freecodecamp.org/how-to-design-a-serverless-async-api-6cfd68939459

I recently ran a workshop to teach developers how to create an Alexa skill. The workshop material centered around a project to return car rental search results. Because I wanted to focus the learning on developing the conversational flow and not the mechanics of doing a car search, I decided to encapsulate the search logic behind an API. In addition, since the car search request can take 10 or more seconds to complete, I wanted the call to be asynchronous so we could build a conversation like:

The implementation of the asynchronous API was a pretty interesting project in and of itself, and in this blog post I’m going to tell you how I did this in a serverless way using API Gateway, Lambda functions, and S3.