# Generate SDKs for REST APIs in API Gateway
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To call your REST API in a platform- or language-specific way, you must generate the platform- or language-specific SDK of the API. You generate your SDK after you create, test, and deploy your API to a stage. Currently, API Gateway supports generating an SDK for an API in Java, JavaScript, Java for Android, Objective-C or Swift for iOS, and Ruby.

This section explains how to generate an SDK of an API Gateway API. It also demonstrates how to use the generated SDK in a Java app, a Java for Android app, Objective-C and Swift for iOS apps, and a JavaScript app. 

To facilitate the discussion, we use this API Gateway [API](simple-calc-lambda-api.md), which exposes this [Simple Calculator](simple-calc-nodejs-lambda-function.md) Lambda function. 

Before proceeding, create or import the API and deploy it at least once in API Gateway. For instructions, see [Deploy REST APIs in API Gateway](how-to-deploy-api.md).

**Topics**
+ [Simple calculator Lambda function](simple-calc-nodejs-lambda-function.md)
+ [Simple calculator API in API Gateway](simple-calc-lambda-api.md)
+ [Simple calculator API OpenAPI definition](simple-calc-lambda-api-swagger-definition.md)
+ [Generate the Java SDK of an API in API Gateway](generate-java-sdk-of-an-api.md)
+ [Generate the Android SDK of an API in API Gateway](generate-android-sdk-of-an-api.md)
+ [Generate the iOS SDK of an API in API Gateway](generate-ios-sdk-of-an-api.md)
+ [Generate the JavaScript SDK of a REST API in API Gateway](generate-javascript-sdk-of-an-api.md)
+ [Generate the Ruby SDK of an API in API Gateway](generate-ruby-sdk-of-an-api.md)
+ [Generate SDKs for an API using AWS CLI commands in API Gateway](how-to-generate-sdk-cli.md)