Cloudformation template for fastmail MX/SPF/DKIM records described on https://www.fastmail.com/help/receive/domains-setup-mxonly.html

cloudformation-fastmail-mx-spf-dkim.yml

Parameters:

  Domain:
    Description: Domain for hosted zone, e.g. example.com
    Type: String

Resources:

  WebHostedZone:
    Type: AWS::Route53::HostedZone
    Properties:
      Name: !Ref Domain

  WebMailRecordSetGroup:
    Type: AWS::Route53::RecordSetGroup
    Properties:
      HostedZoneId: !Ref WebHostedZone
      RecordSets:
        - Name: !Ref Domain
          TTL: 21600
          Type: MX
          ResourceRecords:
            - 10 in1-smtp.messagingengine.com
            - 20 in2-smtp.messagingengine.com
        - Name: !Ref Domain
          TTL: 21600
          Type: TXT
          ResourceRecords:
            - "\"v=spf1 include:spf.messagingengine.com ?all\""
        - Name: !Join ["", ["fm1._domainkey.", !Ref Domain]]
          TTL: 21600
          Type: CNAME
          ResourceRecords:
            - !Join ["", ["fm1.", !Ref Domain, ".dkim.fmhosted.com"]]
        - Name: !Join ["", ["fm2._domainkey.", !Ref Domain]]
          TTL: 21600
          Type: CNAME
          ResourceRecords:
            - !Join ["", ["fm2.", !Ref Domain, ".dkim.fmhosted.com"]]
        - Name: !Join ["", ["fm3._domainkey.", !Ref Domain]]
          TTL: 21600
          Type: CNAME
          ResourceRecords:
            - !Join ["", ["fm3.", !Ref Domain, ".dkim.fmhosted.com"]]

Outputs:
  HostedZoneId:
    Description: Hosted Zone ID
    Value: !Ref WebHostedZone
  WebMailDomain:
    Description: Mail RecordSetGroup Domain Name
    Value: !Ref WebMailRecordSetGroup