An AWS CloudFormation template for adding a custom domain to an API deployed with API Gateway

api_custom_domain.yaml

AWSTemplateFormatVersion: 2010-09-09

Parameters:

  ApiId:
    Type: String
    Description: The ID of the API for which to create the custom domain

  ApiStage:
    Type: String
    Description: The API stage to associate with this custom domain
    
  CustomDomainName:
    Type: String
    Description: The custom domain name to use for the API

  HostedZone:
    Type: String
    Description: The Route 53 hosted zone corresponding to the custom domain

Resources:

  DomainCertificate:
    Type: AWS::CertificateManager::Certificate
    Properties:
      DomainName: !Ref CustomDomainName
      ValidationMethod: DNS

  DomainName:
    Type: AWS::ApiGateway::DomainName
    Properties:
      RegionalCertificateArn: !Ref DomainCertificate
      DomainName: !Ref CustomDomainName
      EndpointConfiguration:
        Types:
          - REGIONAL

  BasePathMapping:
    Type: AWS::ApiGateway::BasePathMapping
    Properties:
      DomainName: !Ref DomainName
      RestApiId: !Ref ApiId
      Stage: !Ref ApiStage

  RecordSet:
    Type: AWS::Route53::RecordSet
    Properties:
      AliasTarget:
        DNSName: !GetAtt DomainName.RegionalDomainName
        HostedZoneId: !GetAtt DomainName.RegionalHostedZoneId
      HostedZoneName: !Ref HostedZone
      Name: !Sub "${CustomDomainName}."
      Type: A