How to connect an AWS Lambda function to a REST API

How to integrate your Lambda function with Amazon API Gateway and a REST API:

1. Go to the AWS Management Console: Navigate to the Amazon API Gateway service.
2. Create a new API: Click on “Create API”. You will be presented with several options. Select “REST API” and click “Build”.
3. Configure your REST API:
   • API name: Give your API a name.
   • Endpoint Type: Choose “Regional”.
4. Create a new resource:
   • Click on the “Actions” dropdown and select “Create Resource”.
   • Enter a “Resource Name”. This will also auto-populate “Resource Path”. Click “Create Resource”.
5. Create a new method:
   • Click on the “Actions” dropdown and select “Create Method”.
   • In the dropdown list under your resource, select “POST” and then click the checkmark.
6. Connect your API Gateway with your Lambda Function:
   • Integration type: Select “Lambda Function”.
   • Use Lambda Proxy integration: Select this checkbox (this allows the API Gateway to forward all incoming data directly to the Lambda function).
   • Lambda Function: Enter the name of your previously created Lambda function.
   • Click “Save”.
7. Deploy your API:
   • Click on the “Actions” dropdown and select “Deploy API”.
   • You’ll be asked to select or create a new “Deployment stage”. You can create a new stage (like ‘prod’ or ‘dev’).
   • After deploying, you will receive an “Invoke URL”. This is the URL that you can call from your React application.

This way, when the POST request hits the API Gateway, the request data will be forwarded to your AWS Lambda function. Your Lambda function will then process the request and return a response which gets sent back to the React app via the API Gateway.

Remember to replace the placeholder URL in the React code with your API Gateway URL.