The document discusses using Google Cloud Endpoints to build a backend API on App Engine. It describes setting up a sample project to demonstrate creating and accessing a RESTful API from App Engine to retrieve cat photo entries. Code examples show defining an Entry entity class, populating an EntryList, and annotating the EntryList class as an API endpoint to retrieve entries by ID. Running mvn commands generates client libraries that can be used by frontend clients to access the API.
This document describes Amazon Web Services (AWS) API Gateway and how it can be used to create, publish, maintain, monitor, and secure APIs at any scale. API Gateway sits between the internet and AWS services such as Lambda, EC2, DynamoDB, and supports many features including caching, authorization, throttling, monitoring, and transformations. It allows defining RESTful APIs and WebSocket APIs that make AWS services programmatically accessible to developers building mobile, web, and IoT applications.