KumoMTA is the only true Open-Source PowerMTA alternative, capable of matching performance of several million messages per hour while providing granular traffic shaping configuration and automation across unlimited IPs.
PowerMTA Alternatives
PowerMTA is described as 'Email gateway application (SMTP server) that makes it easy for senders to adopt the latest authentication specifications ( SPF and DKIM) to comply with changing ISP policies for accountable outbound email delivery. No over hype. It just delivers' and is an app in the office & productivity category. There are 1 alternatives to PowerMTA for Self-Hosted. The best PowerMTA alternative is KumoMTA, which is both free and Open Source.