I've been using maddy as a personal and business email server for a while. Resource consumption is basically zero, no problems with sending or receiving emails

I've been using maddy as a personal and business email server for a while. Resource consumption is basically zero, no problems with sending or receiving emails at all. It did take me quite a few hours to properly set up a Kubernetes + Terraform config though. Getting all the bits and pieces for DKIM, SPF, DMARC right, including issuing certs via cert-manager, is quite finicky.