Serverless Stack API + Vercel

/*
  Certificate ARN: AWS's ARN to the generated domain certificate
   ie: 'arn:aws:acm:us-east-1:1234567890:certificate/12345678-1234-1234-1234-123456789012'
  Domain Name: The Url where it will listen
*/
const { CERTIFICATE_ARN, DOMAIN_NAME } = process.env;

export default class MyAPIStack extends sst.Stack {
  constructor(scope: sst.App, id: string, props?: sst.StackProps) {
    super(scope, id, props);

    // Create a HTTP API
    const api = new sst.Api(this, "Api", {
      routes: {
        "GET /": "src/lambda.handler",
      },
      customDomain: {
        isExternalDomain: true,
        domainName: DOMAIN_NAME,
        certificate: Certificate.fromCertificateArn(this, 
          'Certificate', 
          CERTIFICATE_ARN
        ),
      }
    });

    // Show the endpoint in the output
    this.addOutputs({
      "ApiEndpoint": api.url,
      "ApiDomainUrl": api.apiGatewayDomain?.regionalDomainName || '',
    });
  }
}

Intro

To create super simple Serverless API, Im using Serverless Stack, which is built on top of AWS CDK Infrastructure as a Code solution. You can easily create an API with some lambda functions in a couple of minutes and start from a typescript bolilerplate

npx create-serverless-stack@latest aws-sst --language typescript

Usage

In the case you are not managing your domain in AWS Route53, you will need to create a custom domain and link it to vercel.

You can validate all first level subdomains for your company (*.mycompany.com) using DNS checker to vercel by adding the TXT domain that AWS provides.

Once deployed the snippets will output a Regional endpoint that's different from the API Gateway Endpoint. All Regional solutions will have a d- prefix.

Using the Regional Endpoint, create a CNAME record on vercel domain manager pointing to this generated endpoint.