What Is Amazon API Gateway?
Amazon API Gateway consists of two services: the API Gateway control service and API Gateway execution service. The control service lets you create a RESTful API to expose selected back-end features. The back end can be another AWS service, such as AWS Lambda or Amazon DynamoDB, or it can be an existing web application. The execution service lets an app call the API to access the exposed back-end features. The app can interact with the API using standard HTTP protocols or using a platform- or language-specific SDK generated by the API creator.
The API you create in API Gateway consists of a set of resources and methods. A resource is a logical entity that can be accessed through a resource path using the API. A resource can have one or more operations that are defined by appropriate HTTP verbs such as GET, POST, and DELETE. A combination of a resource path and an operation identify a method in the API. Each method corresponds to a REST API request submitted by the user of your API and the corresponding response returned to the user. API Gateway integrates the method with a targeted back end by mapping the method request to an integration request acceptable by the back end and then mapping the integration response from the back end to the method response returned to the user. As an API developer, you can configure how methods are mapped to integrations and vice versa by stipulating what parameters to use and specifying mapping templates to transform payloads of given data models.
You can create an API by using the API Gateway management console, described in Getting Started, or by using the API Gateway API Gateway REST API. In addition, you can integrate API creation with AWS CloudFormation templates or API Gateway Extensions to Swagger. For a list of regions where API Gateway is available, as well as the associated control service endpoints, see Regions and Endpoints.
API Gateway helps developers deliver robust, secure, and scalable mobile and web application back ends. API Gateway allows developers to securely connect mobile and web applications to business logic hosted on AWS Lambda, APIs hosted on Amazon EC2, or other publicly addressable web services hosted inside or outside of AWS. With API Gateway, developers can create and operate APIs for their back-end services without developing and maintaining infrastructure to handle authorization and access control, traffic management, monitoring and analytics, version management, and software development kit (SDK) generation.
API Gateway is designed for web and mobile developers who want to provide secure, reliable access to back-end APIs for access from mobile apps, web apps, and server apps that are built internally or by third-party ecosystem partners. The business logic behind the APIs can either be provided by a publicly accessible endpoint that API Gateway proxies call, or it can be entirely run as a Lambda function.
To better understand the terminology used in this documentation, you may find it useful to peruse the API Gateway Concepts section.