When we launched Postmark, we prioritized email authentication with DKIM and SPF to establish a strong reputation. While some might view this as a complex process, our platform handles it for customers, providing two key options: signing messages on our own domain or adding records to their DNS to sign messages on their behalf. We recommend the former approach, as it aligns with industry trends and allows customers to build their reputation on their own domain. Additionally, we're working on improving our DKIM process by allowing customers to delegate a subdomain, making it easier for them to manage their reputation without requiring manual updates from us.