CloudFormation template for setting up custom domain name for an API in API Gateway.

API_Gateway_set-up-custom-domain.yml

AWSTemplateFormatVersion: "2010-09-09"
Description: "Setup API Gateway custom domain name"
Parameters:
  AcmArn:
    Type: String
  CustomDomainName:
    Type: String
  ApiID:
    Type: String
  DomainHostZoneId:
    Type: String
Resources:
  ApiGatewayCustomDomainName:
    Type: "AWS::ApiGateway::DomainName"
    Properties:
      CertificateArn: !Ref AcmArn
      DomainName: !Ref CustomDomainName
BasePathMapping:
    Type: "AWS::ApiGateway::BasePathMapping"
    DependsOn: ApiGatewayCustomDomainName
    Properties:
      DomainName: !Ref CustomDomainName
      RestApiId: !Ref ApiID
      Stage: api
CustomDomainRecord:
    Type: "AWS::Route53::RecordSet"
    Properties:
      Name: !Ref CustomDomainName
      Type: A
      HostedZoneId: !Ref DomainHostZoneId
      AliasTarget:
        DNSName: !GetAtt ApiGatewayCustomDomainName.DistributionDomainName
        HostedZoneId: !GetAtt ApiGatewayCustomDomainName.DistributionHostedZoneId