Why API Gateway matters in AWS - Why It Works

Introduction

When you build apps that talk to other apps or services, you need a way to manage those conversations safely and smoothly. API Gateway helps by acting like a smart gatekeeper that controls who can talk, what they can say, and how the messages get through.

When you want to let mobile apps securely access your backend services without exposing them directly

When you need to control and limit how many requests users can send to your service to avoid overload

When you want to transform or validate incoming requests before they reach your backend

When you want to collect data about how your APIs are used for monitoring and troubleshooting

When you want to connect multiple backend services under one easy-to-use URL

Commands

This command creates a new API Gateway REST API named MyExampleAPI in the us-east-1 region. It's the first step to set up your API Gateway.

Terminal

aws apigateway create-rest-api --name MyExampleAPI --region us-east-1

Expected Output

{

    "id": "a1b2c3d4e5",

    "name": "MyExampleAPI",

    "createdDate": "2024-06-01T12:00:00Z",

    "region": "us-east-1"

}

→

--name - Sets the name of the new API

→

--region - Specifies the AWS region where the API is created

This command lists all REST APIs in the us-east-1 region so you can verify that your API was created successfully.

Terminal

aws apigateway get-rest-apis --region us-east-1

Expected Output

{

    "items": [

        {

            "id": "a1b2c3d4e5",

            "name": "MyExampleAPI",

            "createdDate": "2024-06-01T12:00:00Z"

        }

    ]

}

→

--region - Specifies the AWS region to list APIs from

This command creates a new resource path called /example under the root resource of your API. Resources are like folders or endpoints in your API.

Terminal

aws apigateway create-resource --rest-api-id a1b2c3d4e5 --parent-id a1b2c3d4e5 --path-part example --region us-east-1

Expected Output

{

    "id": "f6g7h8i9j0",

    "parentId": "a1b2c3d4e5",

    "pathPart": "example",

    "path": "/example"

}

→

--rest-api-id - Specifies which API to add the resource to

→

--parent-id - Specifies the parent resource ID, usually the root

→

--path-part - Sets the name of the new resource path

→

--region - Specifies the AWS region

This command adds a GET method to the /example resource without requiring authorization. Methods define what actions users can perform on resources.

Terminal

aws apigateway put-method --rest-api-id a1b2c3d4e5 --resource-id f6g7h8i9j0 --http-method GET --authorization-type NONE --region us-east-1

Expected Output

{

    "httpMethod": "GET",

    "authorizationType": "NONE",

    "apiKeyRequired": false

}

→

--http-method - Defines the HTTP method like GET, POST, etc.

→

--authorization-type - Sets the security type; NONE means open access

This command lists all resources and methods in your API so you can check your setup.

Terminal

aws apigateway get-resources --rest-api-id a1b2c3d4e5 --region us-east-1

Expected Output

{

    "items": [

        {

            "id": "a1b2c3d4e5",

            "path": "/"

        },

        {

            "id": "f6g7h8i9j0",

            "path": "/example",

            "resourceMethods": {

                "GET": {}

            }

        }

    ]

}

→

--rest-api-id - Specifies which API to list resources from

→

--region - Specifies the AWS region

Key Concept

If you remember nothing else from this pattern, remember: API Gateway acts as a secure and manageable front door for your backend services.

Common Mistakes

Trying to create a resource without specifying the correct parent ID

The resource won't be created because the parent resource ID is required to place the new resource in the API structure

Always get the root resource ID first using 'aws apigateway get-resources' and use it as the parent ID

Not specifying the region in AWS CLI commands

Commands may fail or act on the wrong region, causing confusion or errors

Always include the --region flag or configure a default region in your AWS CLI settings

Setting authorization-type to NONE in production without other security measures

This leaves your API open to anyone, risking misuse or attacks

Use proper authorization methods like IAM roles, API keys, or Cognito for secure access

Summary

Create an API Gateway REST API to act as the entry point for your backend services.

Add resources and methods to define the API structure and allowed actions.

Use AWS CLI commands to create, verify, and manage your API setup step-by-step.